Phase II and Phase III Archeological Database and Inventory Site Number: 18PR390 Site Name: Riversdale Prehistoric Other name(s) Calvert Mansion Historic
Brief late 18th-19th century plantation house Unknown Description:
Site Location and Environmental Data: Maryland Archeological Research Unit No. 11 SCS soil & sediment code BuB,BuD Latitude 38.9619 Longitude -76.9428 Physiographic province Western Shore Coastal Terrestrial site Underwater site Elevation m Site slope 0-15% Ethnobotany profile available Maritime site Nearest Surface Water
Site setting Topography Ownership Name (if any) Northeast Branch -Site Setting restricted Floodplain High terrace Private Saltwater Freshwater -Lat/Long accurate to within 1 sq. mile, user may Hilltop/bluff Rockshelter/ Federal Ocean Stream/river need to make slight adjustments in mapping to cave Interior flat State of MD account for sites near state/county lines or streams Estuary/tidal river Swamp Hillslope Upland flat Regional/ Unknown county/city Tidewater/marsh Lake or pond Ridgetop Other Unknown Spring Terrace Low terrace Minimum distance to water is m
Temporal & Ethnic Contextual Data: Contact period site ca. 1820 - 1860 Y Ethnic Associations (historic only)
Paleoindian site Woodland site ca. 1630 - 1675 ca. 1860 - 1900 Y Native American Asian American Archaic site MD Adena ca. 1675 - 1720 ca. 1900 - 1930 African American Unknown Early archaic Early woodland ca. 1720 - 1780 Post 1930 Anglo-American Y Other MIddle archaic Mid. woodland ca. 1780 - 1820 Y Hispanic Late archaic Late woodland Unknown historic context Unknown prehistoric context Unknown context Y=Confirmed, P=Possible
Site Function Contextual Data: Historic Furnace/forge Military Post-in-ground Urban/Rural? Rural Other Battlefield Frame-built Domestic Prehistoric Transportation Fortification Masonry Homestead Multi-component Misc. ceremonial Canal-related Encampment Other structure Farmstead Village Rock art Road/railroad Townsite Slave related Hamlet Shell midden Mansion Wharf/landing Religious Non-domestic agri Plantation Base camp STU/lithic scatter Maritime-related Church/mtg house Recreational Rockshelter/cave Quarry/extraction Row/townhome Bridge Ch support bldg Cellar Midden/dump Earthen mound Fish weir Ford Burial area Cairn Production area Privy Artifact scatter Educational Cemetery Burial area Unknown Industrial Spring or well Commercial Sepulchre Other context Mining-related Trading post Isolated burial Unknown Quarry-related Store Other context Mill Bldg or foundation Tavern/inn Black/metalsmith Possible Structure
Interpretive Sampling Data: Prehistoric context samples Soil samples taken N Historic context samples Soil samples taken N Flotation samples taken N Other samples taken Flotation samples taken N Other samples taken Phase II and Phase III Archeological Database and Inventory Site Number: 18PR390 Site Name: Riversdale Prehistoric Other name(s) Calvert Mansion Historic
Brief late 18th-19th century plantation house Unknown Description:
Diagnostic Artifact Data: Prehistoric Sherd Types Shepard Keyser
Projectile Point Types Koens-Crispin Marcey Creek Popes Creek Townsend Yeocomico Clovis Perkiomen Dames Qtr Coulbourn Minguannan Monongahela Hardaway-Dalton Susquehana Selden Island Watson Sullivan Cove Susquehannock Palmer Vernon Accokeek Mockley Shenks Ferry Kirk (notch) Piscataway Wolfe Neck Clemson Island Moyaone Kirk (stem) Calvert Vinette Page Potomac Cr
Le Croy Selby Bay Historic Sherd Types Ironstone 57 Staffordshire Stoneware Earthenware English Brown Morrow Mntn Jacks Rf (notch) Jackfield Tin Glazed Astbury Eng Dry-bodie Guilford Jacks Rf (pent) Mn Mottled Whiteware 396 Borderware Brewerton Madison/Potomac Nottingham North Devon Porcelain 106 Buckley Rhenish Otter Creek Levanna Pearlware 94 Creamware 111 All quantities exact or estimated minimal counts Wt Salt-glazed
Other Artifact & Feature Types: Prehistoric Features Lithic Material Fer quartzite Sil sandstone Prehistoric Artifacts Other fired clay Mound(s) Storage/trash pit Jasper Chalcedony European flint Flaked stone 41 Human remain(s) Midden Burial(s) Chert Ironstone Basalt Ground stone Modified faunal Shell midden Ossuary Rhyolite Argilite Unknown Stone bowls Unmod faunal Postholes/molds Unknown Quartz Steatite Other Fire-cracked rock Oyster shell House pattern(s) Other Quartzite Sandstone
Other lithics (all) 1 Floral material Palisade(s) Dated features present at site Ceramics (all) Uncommon Obj. Hearth(s) Numerous features containing diagnostic historic Rimsherds Other Lithic reduc area artifacts
Historic Artifacts Historic Features Tobacco related 3 Privy/outhouse Depression/mound Unknown Pottery (all) 1145 Activity item(s) 986 Const feature Well/cistern Burial(s) Other Glass (all) 4103 Human remain(s) Foundation Trash pit/dump Railroad bed structures,walls Architectural 7073 Faunal material Cellar hole/cellar Furniture 119 Misc. kitchen 1760 Sheet midden Earthworks Hearth/chimney Arms 10 Floral material Planting feature Mill raceway Postholes/molds Clothing 29 Misc. 4037 Road/walkway Wheel pit Personal items 18 Other tar, slag, rubber, Paling ditch/fence All quantities exact or estimated minimal counts coal
Radiocarbon Data: Sample 1: +/- years BP Reliability Sample 2: +/- years BP Reliability Sample 3: +/- years BP Reliability
Sample 4: +/- years BP Reliability Sample 5: +/- years BP Reliability Sample 6: +/- years BP Reliability
Sample 7: +/- years BP Reliability Sample 8: +/- years BP Reliability Sample 9: +/- years BP Reliability
Additional radiocarbon results available Phase II and Phase III Archeological Database and Inventory Site Number: 18PR390 Site Name: Riversdale Prehistoric Other name(s) Calvert Mansion Historic
Brief late 18th-19th century plantation house Unknown Description:
External Samples/Data: Collection curated at MNCPPC Additional raw data may be available online
Summary Description: Riversdale Mansion (18PR390) is an early 19th century Calvert family plantation house in the town of Riversdale Park, Maryland. The site is situated on a relict terrace on the floodplain of the Northeast Branch of the Anacostia River. Prior to the early 18th century, most of the Riverdale area probably was forested. By the middle of the 19th century, farms covered much of the landscape with woodlots preserved in those areas less suited to tobacco and grain agriculture. Today, the roughly 7+ acre Riversdale property is surrounded by urban/residential development. Beltsville-Urban Complex soils encompass much of the surrounding landscape. Originally well-drained silt loams and fine sandy loams on top of compact fragipan, 20th century residential and commercial development has extensively disturbed the soils in the area.
The Riversdale Mansion, also known as the “Calvert Mansion”, was built around 1802 and was originally part of an 800 acre estate and plantation. Riversdale is extremely large by early 19th century standards. The neo-classical (Federal) style, popular during this period, was adapted with a two-story main house and outstretched wings. The house was entered through a north portico with four Doric columns. A parlor was located on the west and a dining room was on the east side of a principal salon or drawing room. Although the kitchen may have been located originally in an outbuilding, and later in the cellar, it eventually occupied the south part of the east wing. Utility rooms such as stair halls and storage space were located on the north while principal living rooms enjoyed the southern exposure.
Five phases of archeological work have been conducted at Riversdale (18PR390) over the years. Extensive archival research into the history of Riversdale was conducted during the various research projects. However, much work remains to be done as many of the source records are in French (due to the Belgian heritage of some of the earliest occupants). The archival evidence reveals that the mansion was built by Baron Joseph Stier, a wealthy Belgian aristocrat who fled the French Revolution’s invading armies with his family in 1794. The family included his wife, Marie Louise Peeters Stier (1748-1804), their son, Charles Jean and his wife, Marie Van Havre Stier; a daughter, Isabelle, and her husband, Baron Jean Van Havre; and their youngest child Rosalie Eugenia.
The Stiers landed in the United States at Philadelphia where they remained about a year before settling in the vicinity of Annapolis, Maryland. During this period, Rosalie Stier (1778-1821) met and married (1799) George Calvert (1768-1838). Calvert was a direct descendent of the Lords Calvert, founders of Maryland, and was a member of the state legislature. The couple took residence as George’s home, Mt. Airy. In April 1801, Baron Stier purchased the 800 acre estate that was to be called Riversdale. Construction of the mansion began almost immediately, while the family lived in a house in nearby Bladensburg. The new home was based on an architectural design created by Benjamin Henry Latrobe for “Gamble Hill”, home of Colonel John Harvie in Richmond, Virginia. It follows the Gamble Hill plan very closely. Brick for Stier’s house was made of clay found and fired on the property. Interpretations vary, but, by 1802 the Stiers inhabited their home, though it was still under construction.
By 1802, the political climate in Europe had changed so radically that the Stiers began to yearn for their former home in the old country. Charles Jean Stier had returned to Belgium in 1801. In 1803 the elder Stiers, Isabelle, and her husband also went back to Europe leaving Rosalie and George Calvert to oversee the completion of Riversdale. In addition to having an American husband, Rosalie had fallen in love with America in a way that her parents and other relatives had not. Although she hoped to rejoin her parents, at least for a visit, they were in fact never to see each other again.
It is precisely because this reunion never occurred that a significant body of correspondence was exchanged between Rosalie and her family. In nearly every letter that has been translated, Rosalie faithfully reports on the progress made toward finishing and furnishing the mansion. The letters describe details as to the type of cornices, chandeliers, mantle pieces, sofas, portraits, lamps and mirrors inside the house. Outdoor improvements to gardens, fences, walkways, other landscaping concerns and outbuildings are detailed as well. Of particular interest to both Rosalie and her father are the gardens and bulbs established by Baron Henri before his departure. He was apparently an avid gardener and it fell to Rosalie to care for his prized bulbs.
For the next 8 decades Riversdale, which came to be known as the Calvert Mansion, was occupied by the heirs and descendents of George and Rosalie Calvert. Rosalie died in 1821, shortly before the death of her father. George Calvert retained all the property of Baron Stier in America in trust for Rosalie’s five surviving children. The claims of the three daughters, Caroline Marie, Rosalie Eugenia, and Julia, were settled by grants of farms, plantations, or other properties formerly owned by Baron Stier. Each sibling also inherited a 1/5 interest in Riversdale. The two sons, George Henry and Charles Benedict, obtained half shares in what remained when their father died in 1838.
When George Calvert died, an inventory of his personal estate enumerated the furnishings within the house. Between the time Charles Benedict Calvert took charge in 1838, and his death in 1864, Riversdale witnessed some important events and persons of the mid 19th century. It became a model farm through the efforts of its proprietor and was publicized often in the national agricultural press. Calvert’s octagonal barn and elaborate manuring, water management, and milking systems were innovative and much admired (even if impractical for the common farmer to afford). In 1856, Charles Benedict Calvert would be instrumental in founding the Maryland Agricultural College, which later became the University of Maryland. He also was involved heavily in the movement to create a federal Department of Agriculture, eventually established by Congress in 1862. The first telegraphy line was tested in front of the Calvert Mansion by Samuel F.B. Morse in 1844. Many notable figures of the times were frequent guests, including Henry Clay, who was there so often that he had his own room. Charles represented his county in the state legislature in 1839, 1843, and 1844, and was elected to the U.S. House of Representatives in 1861.
Changes made to the house during Benedict’s tenure include the building of an elaborate system of drains, water towers, and waterclosets; the installation of a coal-fired furnace sometime before 1861, and the bricking up of foundation arches in the cellar under the library room. Charles Benedict Calvert died in 1864 and another inventory of the estate was taken.
Charlotte Calvert, Charles Benedict’s widow, continued to live at the mansion until her death in 1876. George Henry Calvert Jr., Benedict’s son and heir, resided at Riversdale until 1887, when the property was sold to a New York development firm. In the six decades or so that followed, the house was used for several purposes. It was a headquarters building for the development company’s surveyors, a boarding house, the Lord Baltimore Country Club, and the home of several United States Congressmen. In May 1949, the Calvert Mansion was acquired by the Maryland National Capital Park and Planning Commission (MNCPPC) for use as its headquarters (and eventually as an interpretive center).
In 1988, a Phase I investigation was conducted at the site to examine the basement of the structure as well as areas beneath the south portico prior to Phase II and Phase III Archeological Database and Inventory Site Number: 18PR390 Site Name: Riversdale Prehistoric Other name(s) Calvert Mansion Historic
Brief late 18th-19th century plantation house Unknown Description: renovation of the mansion. Among the goals of the project were the determination of the original basement floor elevations and the identification of the original surface materials of these floors where archeological evidence was available. The site was investigated with the excavation of 25 formal test units during the 1988 Phase I work. Typically, this type of extensive work would be on par with Phase II testing.
Test units were placed in each of the ten rooms in the basement and in the area beneath the south portico in locations judged most likely to intercept relevant features. Twenty-three 91 X 91 cm (3 X 3 ft) test units were excavated in the basement proper in basement rooms numbered 1-8, and two 91 X 91 cm units beneath the portico (Rooms 9-10), a total of approximately 9% of the available area. All test units were hand excavated according to natural strata. Stratigraphy and full soil descriptions were recorded on standardized forms and all significant profiles and plan views were photographed and drawn to scale. Soil from each unit was screened through mesh hardware cloth.
The 1988 excavations at Riversdale were quite revealing. It appears from the data recovered that a herringbone brick floor observed in the central block of basement rooms represents the original floor surface in the basement, installed during the initial construction of the house. No floor surfaces or occupational horizons were visible below the herringbone brick. Subsurface deposits across the basement as a whole consisted of a series of fill layers, composed in the main of re-deposited subsoil and containing construction materials and a relatively small amount of domestic debris. Diagnostic artifacts contained within the domestic materials tended to confirm the notion that no earlier floors existed in the basement: early and late ceramics, glass bottle fragments and nails were encountered at various levels within the fill deposits. There was an indication based on a very small ceramic sample that the deposits below the floor surface in the central block date to the period of house construction, the turn of the 19th century.
In several cases there was evidence of the original construction procedures within the basement. It appears that after the basement was excavated, the house walls were laid directly against the walls of the pit on only a thin layer of leveling fill. A comparatively minor amount of subsoil was the re-introduced to level the floor surface, a bed of packed sand laid, and the floor brick put into place. The presence of artifactual materials in the redeposited subsoil suggests that it was stockpiled for a period of time outside the cellar. There is no indication of a builder’s trench along the interior of the house walls, as would be expected if the wall footing extended deeply below floor level.
Ground water problems did require the use of a deep footing in the southwest corner of the central block, Room 3, and the installation of a sub-floor drainage system, the latter showing signs of repair work along the east wall of the room. The drain appeared to have continued the length of the west wall of the central block, though only the trench in which it was laid and an exit grating remained as evidence in Room 7. It is not known how far along the east or north walls the drain extended.
In Room 1, the original herringbone floor appeared to have been replaced. Judging from the presence of later 19th century stonewares beneath this floor, the replacement may have taken place sometime after 1850. A drain was installed directly below the floor in Room 1 and 5, probably at the same time that the floor was relaid. No earlier trenching was observed below the trench excavated for this drain, indicating that the drain did not replace an earlier system in the east end of the house.
The original brick floor was missing in several locations in the basement. The floor had been removed from Room 2, for example, but it is not clear when or why the brick was removed. A circular pit-like feature (Feature 10) in the center of the room, a small brick platform in the northwest corner, and a large amount of coal scattered across the room may be related in some way to removal of the bricks, but the evidence is insufficient. Likewise, no explanation can be offered for a lack of brick in the west half of Room 7. A formal edge to the flooring there was observed, suggesting that the unpaved area was an original feature of this room. The original herringbone floor may have been extended into Rooms 9 and 10, beneath the north portico. If so, it has since been replaced by brick laid in a somewhat less formal pattern.
Room 8 was different from the rest of the rooms investigated. It contained very disturbed fill deposits, sandier and deeper than that in other locations. No firm data was recovered (at this stage) concerning a series of arches along the west and south walls of the room. There would appear to have been little need for ornamental arches in a basement wall, unless the original plans called for the west wall to be an exterior wall with fanlights at ground level. Otherwise, the arches are assumed to be functional, even though, as a shallow footing indicated, they seem to be rather low to provide convenient passageway.
Analysis of artifact distributions within the basement failed to indicate specific uses for any cellar rooms, with the possible exception of one room that appeared to have been a general storage area based on a preponderance of redware, stoneware, and yelloware sherds. However, contrary to the perception of the deposits across the basement as undifferentiated fill, a statistically significant variation was shown to exist from room to room. This variation may, in fact, be meaningful archeologically, but comparison to other sites and more detailed analysis is necessary to get at specific functions. The full 1988 Phase I artifact assemblage included 44 activity items, 1,279 architectural artifacts, 1 furniture item (a tack), 796 kitchen-related artifacts, 1 personal item (a porcelain fig), 424 miscellaneous historic objects, and 6 prehistoric artifacts (a rhyolite Orient Fishtail, a quartzite biface, a quartz core, a quartzite core, a quartz utilized flake, and a hammerstone). The activity items were 35 pieces of lamp glass, a piece of non-electrical wire, 6 redware flowerpot fragments, 1 pencil fragment, and a stable item. The architectural remains include 496 pieces of brick, 18 fragments of cement, 5 pieces of concrete, 333 pieces of shell mortar, 61 other pieces of mortar, 4 fragments of asbestos, 20 pieces of shell plaster, 47 pieces of plaster, 211 fragments of window glass, 2 pieces of putty, 7 fragments of architectural stone, 2 fragments of slate, 2 pressboard fragments, 4 pieces of wood, 2 tiles (1 porcelain), 6 marble fragments, 1 piece of drainpipe, 46 nails (1 handwrought, 9 cut, 9 wire, & 27 unidentified), 1 bolt/nut, 2 hardware staples, a porcelain insulator, 7 pieces of architectural hardware, and a miscellaneous architectural object. The kitchen-related objects were 97 ceramic sherds (6 creamware, 6 pearlware, 3 Chinese porcelain, 3 other porcelain, 5 whiteware, 1 ironstone, 4 American stoneware, 9 miscellaneous stoneware, 7 yelloware, 50 redware, and 3 unidentified ceramics), 231 pieces of glass (54 table glass, 8 blown-bottle, 169 unidentified bottle), a bottle cap, and 467 faunal remains (8 pieces of turtle shell, 8 bird bones, 32 mammal bones, 1 unidnetified animal bone, 1 fish scale, 391 oyster shell fragments, 24 clam shell fragments, and 2 pieces of oyster shell). And finally, the miscellaneous objects were 51 metal objects (possible hardware), 2 plastic/synthetic items, a piece of tar, 1 rubber object, 2 unidentified glass shards, 148 pieces ofcoal, 72 pieces of charcoal, 108 cinders, 2 pieces of stone, 15 fragments of slag, 21 unidentified wood fragments, and a piece of burned bark.
A Phase II testing project was conducted at 18PR390 in August and September of 1989 to investigate further the archeological features revealed in the Phase I survey (primarily the drainage system and the circular pit-like feature) and to explore some areas of the grounds where additional restoration work was likely to disturb any archeological features that might be present. Archeological test units were excavated in locations throughout the basement and around the perimeter of the house. Twenty-six units measuring 91 X 91 cm, 14 in the basement and the remaining 12 around the exterior of the mansion, were excavated during Phase II work in 1989. The exterior units include 2 units near the north portico, two units along the exterior of the south portico, 7 units between the eastern wall of the mansion’s east wing and an exterior dependency (kitchen/slave quarters), and a single unit to the southwest of the mansion. Phase II and Phase III Archeological Database and Inventory Site Number: 18PR390 Site Name: Riversdale Prehistoric Other name(s) Calvert Mansion Historic
Brief late 18th-19th century plantation house Unknown Description:
The Phase II excavations in the basement of the mansion allowed a tentative picture of the drainage system to be constructed. The drainage system in the eastern section of basement rooms (Rooms 1 and 5) seems to be distinct from that in the other rooms to the west (Rooms 3, 6, & 7). A possible sump for the eastern drain system was encountered in one unit. The precise layout of the western section of drains and whether they were part of a single western drain system is uncertain. It appears that these drains exited the house via the westernmost Room 8 into a stream or pond. Based on the use of Portland cement as mortar, it is known that the arches in Room 8 were bricked in after the late 19th century. The presence of the arches, the nature of the deposition, and the fact that the drains exit in this area all indicate that water may have flowed through this area. Additional archival work could help confirm this observation.
Testing in the area between the east wing and the kitchen/slave quarter area revealed remnant steps (Feature 19) against the east wall of the mansion, as well as kitchen refuse near both the east wall of the mansion and the door of the slave quarters/kitchen dependency. The steps were completely exposed and recorded, and were bisected by a test unit. The only diagnostic artifacts recovered from beneath the feature were 6 sherds of creamware. The absence of later material, such as whiteware, may indicate that the steps were original with the construction of the mansion. One of the test units in this area revealed deposits that are potentially slave kitchen refuse. These could add greatly to our knowledge of the lifeways of domestic slaves in this part of Prince George’s County. There has been some disturbance to this area due to the construction of a breezeway linking the Dependency to the mansion. Excavation of a unit just to the east of the unit with the kitchen deposits had to abandoned due to the presence of a concrete foundation. It is possible that the refuse deposits extend beneath a modern office addition to this Dependency. A utility trench between this office addition and the mention has disturbed much of that area, likely destroying any archeologically significant remains.
The removal of a set of modern steps in the north portico area revealed another set of remnant brick steps in the front of the portico. These were not original to the construction of the mansion, as excavation revealed that they dated to after ca. 1850. No evidence of earlier steps was found. This area has also seen some disturbance by a utility trench running east-west in front of the portico.
The two test units in the south portico area uncovered the original builder’s trench for the portico, but failed to yield any evidence of the original steps. Unless the steps came off the sides of the portico (no evidence was found to support this), all remains of the original steps were probably destroyed by placement of a very substantial concrete foundation for the modern steps.
The single unit located to the southwest of the mansion was excavated in order to clear this area for construction activities. While a small number of early domestic artifacts were found, this was not felt to represent an archeologically significant deposit and the area was cleared for construction to proceed.
The artifact assemblage from the 1989 Phase II work included 210 activity items, 2,759 architectural objects, 23 clothing remains, 109 furniture objects (108 tacks and a crystal chandelier drop), 1,703 kitchen-related artifacts, 10 personal items, 2 tobacco-related artifacts (a kaolin pipe fragment and a cigarette filter), 5 arms objects (two .22 calber shells and 3 other ammunition shells), 471 miscellaneous historic objects, and 5 prehistoric artifacts (1 utilized flake, 3 quartz flakes, and a pieces of quartz shatter). The activity items were 3 toys (a marble, a lead toy soldier, and a plastic toy soldier), 70 pieces of lamp glass, a piece of non-electric wire, a spark plug, a battery, a triangular file, an iron hoe, a screw, an eye bolt, 2 hooks, 2 metal rings, a chain link, a nut/bolt, a copper strip, 5 iron strips, 7 pieces of miscellaneous hardware, 91 redware flowerpot fragments, a railroad spike, 15 pencil fragments, 3 horseshoes, and a lead printer’s type “9”. Architectural objects were 52 pieces of glazed brick, 102 fragments of other brick, 3 pieces of concrete, 41 shell mortar fragments, 8 pieces of mortar, 2 asphalt tiles, 38 pieces of shell plaster, 26 pieces of plaster, 1,934 window glass fragments, 19 pieces of putty, 2 fragments of architectural stone, 3 pieces of slate, 6 pressboard fragments, 52 pieces of wood, 2 pieces of whitewashed wood, 4 paint flakes, 8 pieces of linoleum, 4 marble fragments, 12 pieces of ceramic drainpipe, a copper alloy drain, 2 pieces of electrical wire, 360 nails (3 handwrought, 98 cut, 51 wire, and 208 unidentified), 7 cut spikes, 2 unidentified spikes, 2 hinges, 2 latches, 2 locks, 58 pieces of architectural hardware, and 4 miscellaneous architectural objects. The clothing items were 15 buttons (2 porcelain, 1 pewter, 6 bone, 3 shell, 2 copper, 1 glass), 3 hooks and eyes, a copper alloy eyelet, 3 pins, and 1 wool strand. The kitchen-related artifacts were 414 ceramic sherds (94 creamware, 71 pearlware, 7 Chinese porcelain, 3 European porcelain, 41 other porcelain, 86 whiteware, 54 ironstone, 13 American stoneware, 8 miscellaneous stoneware, 3 yelloware, 21 redware, 13 unidentified ceramics), 803 fragments of glass (138 table glass fragments, 179 blown bottle shards, 170 20th century bottle shards, and 316 unidentified bottle fragments), a piece of aluminum foil, 9 bottle caps, 3 aluminum pulltabs, 14 aluminum champagne cork foil fragments, a plastic champagne cork, 456 faunal remains (4 pig teeth, 46 bird bones, 204 mammal bones, 11 unidentified animal bones, 1 fish scale, 4 fish bones, 182 oyster shells, 3 clam shells, and 1 egg shell), and 2 floral items (nutshells). Personal objects include 5 mirror fragments, a key, a glass bead, a tortoise shell comb, an 1880 Indian Head penny, and a jewelry/button pin. The miscellaneous objects were 298 unidentified metal objects, 55 synthetic/plastic items, 2 pieces of paper, 2 rubber objects, 11 pieces of glass, 11 pieces of lead, 39 fragments of coal, 19 pieces of charcoal, 29 clinkers, 2 rodent jaws, 2 snail shells, and a piece of mica.
Also in 1989, MNCPPC archeological staff monitored trenching and installation of utility lines at Riverdale. Trenching for waterlines was undertaken with a ‘ditch-witch’, limiting monitoring to the recording of artifacts turned up in the trench spoil. Sewer installation involved use of heavy machinery, resulting in wider trenches in which profiles were recorded. Five areas of brick and mortar rubble were identified, along with varying amounts of 19th and 20th century domestic debris. For the most part, these were just layers of rubble within the soils, but a possible stone footer or foundation and fill containing large amounts of 20th century domestic debris were exposed in one trench. This fill was capped with a layer of clay, probably during improvements made in 1937. No detailed description of the artifacts recovered during the utility trench monitoring in 1989 is available at MHT.
In 1994, a parking area on the eastern side of the property was examined with ground penetrating radar (GPR). The radar identified several anomalies, most of which can be attributed to the failure and repair of the paving material for the parking lot. At least two positive readings, however, occurred in areas where ground-truthing in 1995 led to the discovery of features (see below).
In January- May of 1995, a combined Phase I and Phase II program was carried out at Riversdale. The MNCPPC was proposing the demolition of the east parking lot (the one subject to the GPR survey in 1994) and construction of a new lot in the area of the mansion’s annex (a mid-20th century dwelling). In keeping with the terms of an historic easement granted to the Maryland Historical Trust, MNCPPC commissioned a Phase I survey and Phase II site examination of portions of the Riversdale property. The primary purpose of the investigation was to locate features related to the Riversdale mansion on the grounds of the MNCPPC property.
The first phase of the 1995 project involved systematic shovel testing at 15.24 meter (50 ft) intervals across the north and west lawns. Unless obstructed, technicians excavated units stratigraphically up to 9 cm (0.3 ft) into Pleistocene deposits. All shovel test pits (STPs) were approximately 39.6 cm (1.3 ft) in diameter and all soil was screened through hardware mesh. One hundred and nine shovel tests were excavated, yielding brick, coal, bottle glass, historic ceramics, bone, oyster shell, window glass, mortar, nails, and prehistoric flaked stone. Six loci were defined on the basis of architectural artifact distributions, four of which may be historically significant. All four loci require additional testing to determine the kinds of resources represented, and their horizontal and Phase II and Phase III Archeological Database and Inventory Site Number: 18PR390 Site Name: Riversdale Prehistoric Other name(s) Calvert Mansion Historic
Brief late 18th-19th century plantation house Unknown Description: vertical limits. No significant materials or deposits were located around the location for the new parking lot).
The second stage of the project involved careful mechanical removal of the pavement around the east side of the mansion Dependency (variously called a summer kitchen and slave quarter). The mechanical removal was monitored by archeological personnel. Removal of the pavement revealed numerous structural and non-structural features, as well as deep, extensive deposits of early to mid-20th century fill. Most features were marked with pin flags as soon as they were uncovered, then trowelled (to remove remaining fill soils), mapped and described. The sometimes muddy, often baked, and always difficult clay loam subsoil hindered progress both in the initial stripping and in the subsequent documentation of features. The features were left largely unexcavated. Only artifact pieces subject to vandalism or that had been disturbed by heavy equipment were collected. These were catalogued by the feature with which they were associated. All others were left in situ. Additional materials exposed during the course of grading but unattributable to any one feature were collected and catalogued as unprovenienced artifacts.
Removal of the east parking lot uncovered 10 structures (9 historic) and approximately 110 features; far more than was expected in an area previously disturbed by a parking lot. Structures I and II are the possible remnants of a staircase and retaining wall associated with the garden terraces of Riverdale. Structure III is a small irregular structure, squarish in shape and of unknown function and age. Structure IV is the apparent remains of several shed additions abutting the extant Dependency (the kitchen/slave quarter). Structure V is the remains of a structure known as the water tower or the bell tower. This building abutted the north wall of the extant Dependency and is shown in a late 19th century photograph to have been a 4 storey frame building with weatherboard siding and a hipped roof. A cupola with a bell in it is the feature which assuredly gave the structure its name. Structure VI was located just north of Structure V and may have been a ca. 1803 washhouse mentioned in a letter by Rosalie Calvert. This foundation appears to have been integrated into an 1807 garden wall (also documented in one of Rosalie’s letters) which was exposed during excavation (as Structure VIII). Structure VII is a small brick wall intersecting the north wall of Structure VI, which served an unknown purpose (possibly storage space for firewood to fuel the washhouse or a screen for a gap in the garden wall). Structure VIII is the brick garden wall built in 1807. The only other structure at the site (other than the mansion) that can be definitively tied the Rosalie and George Calvert tenure at Riversdale is the extant Dependency building. Structure IV is a concrete pad (floor or pavement) for a garage or shed present in early 20th century photos, but probably not historically significant. And finally, Structure X is an octagonal foundation thought to be the remains of the conservatory mentioned in an 1888 description of Riversdale. The octagonal shape points to construction during the era of Charles B. Calvert who is known to have constructed an octagonal barn in the vicinity of the present Riverdale Park Elementary schoolyard.
Other features include various fencelines and utility and waterlines of probable mid-19th and early 20th century vintage. Several possible garden features were also encountered, but are of uncertain date. These garden areas consist of irregular or linear patches of soil without much cultural material or texture. Several flowerpot fragment clusters were noted around various structures as well. Round postholes and postmolds were noted around the parking lot, likely part of a fence or boundary chain for the parking area.
Artifacts recovered during the 1995 work at 18PR390 include 64 activity items, 756 architectural objects, 5 clothing artifacts (4 buttons and a thimble), 9 furniture items (7 cement birdbath fragments, the corner of a marble slab, and a lock), 902 kitchen-related artifacts, 4 personal items (an orange plastic bead, a tooth brush, and 2 pieces of a plastic comb), 5 arms objects (ammunition cartridges), 154 miscellaneous historic objects, and 4 prehistoric artifacts (a biface, a quartz flake, and 2 unidentified flaked stone objects). Activity items include 36 porcelain toys, 3 plastic toys, 1 golf ball, a piece of vinyl record, 10 wooden stakes, a putty knife blade, a piece of non-electrical wire, 2 auto license plates, 4 pieces of hardware, 2 fragments of lamp glass, and 3 pieces of barbed wire. Architectural remains were 260 pieces of brick, 1 hexagonal brick, 19 pieces of plaster, 40 fragments of mortar, 12 pieces of concrete, 4 pieces of asphalt, 338 fragments of window glass, a piece of asbestos, 7 fragments of slate, 3 pieces of architectural stone, 3 pieces of flooring tile, 11 pieces of asbestos tile, 7 fragments of roofing shingle, an iron pipe, 5 pieces of sewer pipe, 2 linoleum fragments, 39 nails (11 cut, 9 wire, and 19 unidentified), a door plate, a hinge, and a piece of electrical wire. The kitchen remains were 545 ceramic sherds (3 creamware, 15 pearlware, 49 porcelain, 302 whiteware, 22 unidentified earthenware, 1 American blue/gray stoneware, 47 gray stoneware, 47 miscellaneous stoneware, 21 yelloware, 3 Rockingham, 21 redware, and 14 unidentified sherds), 337 glass fragments (8 pieces of table glass, 30 dark green bottle glass fragments, 14 18th/19th C. bottle glass shards, 51 19th-early 20th C. bottle glass shards, 227 20th C. bottle glass fragments, and 7 pieces of milk glass), 3 utensils, 1 bone knife, 3 pull tabs, and 13 faunal remains (9 animal bones and 4 pieces of oyster shell). The miscellaneous objects were 8 unidentified metal objects, 12 pieces of plastic, a small purple stone, 1 piece of unidentified glass, a wood fragment, 14 pieces of charcoal, 63 fragments of coal, and 54 pieces of slag.
Archeologists examined the site again in 1997 and 2000, conducting Phase II and III investigations in support of efforts to restore the Dependency and the surrounding historic landscape. The information recovered would be used to ensure the accuracy and authenticity of restoration efforts. The project involved ground-penetrating radar (GPR) examination of the yard areas north of the mansion shovel tested in 1995 and data recovery investigation of features and structures located around the extant kitchen/slave quarter Dependency. In addition, a Gradall was used to ground truth GPR anomalies and to examine a concentration of brick identified in 1995.
In the north yard area to the west of the extant formal entrance drive, forty-five GPR transects, spaced 1.524 m (5 ft) apart were placed in an east-west orientation. It was thought that east-west trending radar profiles would better delineate garden features, as the anticipated garden paths ran predominantly north-south. A total of 228 anomalies were plotted on and AutoCAD map of the mansion grounds. The results of the survey indicated that most anomalies occurred as an even depth (approximately 61 cm) below the modern ground surface. Several of these anomalies were subsequently examined using a Gradall.
To the east of the entrance drive, twenty GPR transects were placed at 1.524 m intervals, this time in a north-south orientation. In all, the GPR identified 55 anomalies, several of which suggested the presence of foundations. A Gradall was then used to explore several of these anomalies, in this instance supplemented with three hand-excavated test units of varying size.
Most of the archeological effort in 1997 was focused near the Dependency, where the removal of the east parking lot in 1995 had uncovered a number of foundations and other features. GPR was obviously not needed for this part of the site due to the extensive surface exposure, so work involved mainly unit excavation. The first step was to remove the soils above the plastic laid down during Phase II work to protect the archeological deposits. This was done mechanically, with professional archeologists monitoring the machine excavation of most of the backfill. The remainder of the fill soils above the plastic cover were then removed by hand and the exposed structure walls were cleaned.
Once the overburden was removed, a datum point was established on the north portico of the mansion and excavation units (of varying sizes) were laid out to examine the archeological deposits in, and immediately outside, the six structures in the area. In the case of Structure IV, up to a foot of concrete flooring had to be removed from the Dependency before units could be laid out. Altogether, 19 excavation units (mostly 1.524 X 1.524 m, but some of smaller or irregular sizes) were opened up in this area. Phase II and Phase III Archeological Database and Inventory Site Number: 18PR390 Site Name: Riversdale Prehistoric Other name(s) Calvert Mansion Historic
Brief late 18th-19th century plantation house Unknown Description:
In the summer of 2000, additional effort would be focused on Structure IV (the Dependency), which was slated for restoration. The principal goal of this work was to completely excavate the archeological deposits beneath the concrete floor, as well as sampling the yards and space beneath a brick addition. These investigations were aimed at providing information useful in the restoration of the structure and for public interpretation of the building. Researchers wanted to know what the function of the building may have been, who may have lived there, and what their material lives had been like.
The 1997 and 2000 investigations employed standard archeological techniques and methods. Again, excavation units varied in size and configuration, but all were excavated by natural/cultural strata, as were the features encountered during fieldwork. All excavated soils were screened through hardware mesh and the recovered artifacts were retained for analysis. Standardized unit and feature forms were completed, as appropriate, for each excavated context. Plan view and profiles were drawn for all units and features. As for the machine-excavated trenches, the walls and floors of each trench were cleaned and then plan and profile maps were drawn as appropriate. Black-and-white photographs and color slides were taken of each unit, trench, and feature. The location of all excavations and GPR transects were recorded on project maps of the Riversdale property.
Though a printout of the 1997/2000 excavation artifact database is provided in the appendices of the full site report, no tally or discussion of the historic artifact types recovered is provided, either in the body of the report or in the appendices. That being the case, the historic artifact assemblage is simply minimally estimated at 2,000 miscellaneous artifacts in the artifact tables above. The prehistoric assemblage is described. It consisted of 2 quartz bifaces, 1 quartzite biface fragment, and 22 flakes (18 quartz, 2 quartzite, and 2 chert). None of the prehistoric artifacts are diagnostic.
At least 30 cultural features were encountered during the 1997/2000 excavations at Riversdale. Features included builder’s trenches, clay caps and lenses, postholes and postmolds, robbed out walls and trenches, pits, the remains of brick piers, a brick walkway, rubble pile and other features from structure demolition, hearth and fireplace remnants, and modern disturbances such as utility lines.
Archeological work in the lawn north of the mansion primarily revealed that at some point, probably during the 20th century, the front lawn was graded and re- landscaped, obscuring any earlier features. Remote sensing and excavation uncovered evidence of one or more of these pathways, although only gravel bases remain.
Excavations in 1997 revealed portions of a brick garden wall built during George and Rosalie Calvert’s occupation of the property. This structure, which separated the garden and orchard from the lawn in front of the mansion, extended northward several hundred feet from the northeast corner of the extant Dependency structure. Researchers also re-exposed the foundation of Structure VI, referred to as the “wash house”, though its function remains uncertain. A fireplace identified in the south room suggests that the building served originally as living quarters. In the north room, a puzzling collection of broken bottles was identified, lining the interior of the foundation. The purpose of these broken bottles remains uncertain. It appears clear, however, that whatever its function, Structure VI is contemporary with, and formed a portion of, the garden wall.
Excavations inside and outside of the Dependency (Structure IV) revealed what was previously suspected, that the structure standing today is not the first to be built on the site. With a much larger window provided by the complete removal of the 20th century concrete floor, it became possible to see that an earlier building, constructed about the same time as the mansion, had subsequently been demolished and almost completely rebuilt. The earlier building was slightly smaller than its successor, and was constructed with a gable-end chimney. As with Structure VI, the Dependency appears to have served a domestic function, perhaps a detached kitchen, living quarters, or, quite possibly, both. It was suspected that the people living and working in the Dependency during the first half of the 19th century were probably enslaved African-Americans. The evidence for such a conclusion, both historical and archeological, remains ambiguous.
The old Dependency appears to have been torn down sometime in the middle of the 19th century, during the restructuring of the property undertaken by Rosalie and George Calvert’s son, Charles Benedict. Continuing the tradition of agricultural experimentation begun by his parents, Charles Benedict Calvert undertook a program of improvements, the most notable being the livestock complex, including the octagonal barn constructed north of the mansion by the early 1850s. Archeological evidence indicates that the Dependency was dismantled around this time, and quite thoroughly. The foundations on three sides of the building were removed and rebuilt, the old footing trenches filled, and layers of clay and brick rubble (apparently including bricks that could not be recycled) spread across the yard west of the Dependency. Once again, the structure appeared to have functioned as a residence, although, as before the identity of the residents is uncertain. Both the 1850 and 1860 censuses list several European-American households, including, in both years, that of a gardener possibly residing in outbuildings at Riversdale. Slaves may also have lived in one or the other of these buildings.
Among his other improvements to the Riversdale property, Charles Benedict Calvert also oversaw the construction of an imposing four storey water tower located between the Dependency and Structure VI. Pipes radiating out from this building, documented during the 1995 and 1997 archeological investigations, may have supplied water to the gardens and, quite possibly, to the privy (Structure III) that had been constructed behind the Dependency.
In April of 2001, the MNCPPC archeology program conducted additional excavation at the Riversdale Dependency as part of the ongoing restoration activities. Excavations were required for two reasons: 1) in order to implement a drainage plan for the yard area between the Dependency and Riversdale Mansion, and 2) because it was determined that the extant historic brick walk was unsuitable for ADA access to the Dependency and had to be replaced with modern materials.
A total of four units were excavated by MNCPPC. Three units (each approximately 91 X 152 cm) dependency were excavated to document the removal of the brick walk between the south doorway of the Dependency and the main house. One additional unit (30.5 X 123 cm) was excavated within the interior hearth in the south room of the Dependency to remove fill before restoration mason installed a new base for the brick hearth. All units were excavated by natural stratigraphy and all soil matrix was screened. All cultural artifacts from intact contexts were saved. Elevations and measurements were taken in engineering scale. The elevations for the three exterior units were taken with a line level from the bottom of the south doorsill. Elevations for the single interior unit were taken with a line level tied to an extant piece of fireplace hardware, set into the east side of the south hearth interior.
Three features were uncovered while excavating the three exterior units. These included a builder’s trench for the Depedency itself, a brick rubble feature from the destruction of the earlier residential/kitchen structure (see above), and a posthole (possibly a scaffolding post, lamp post, or fence post). Both the builder’s trench and posthole underlay the 19th century brick walk, but cut through a clay cap. This suggests construction of the extant dependency before construction of the sidewalk (dated to sometime after 1865 based on an underlying Indian Head penny) and after the lying of the clay cap, suggesting a mid 19th century construction date for the extant building. Phase II and Phase III Archeological Database and Inventory Site Number: 18PR390 Site Name: Riversdale Prehistoric Other name(s) Calvert Mansion Historic
Brief late 18th-19th century plantation house Unknown Description:
The single interior unit did not reveal the presence of any intact features.
Artifacts recovered in 2001 consisted of some 547 objects. The assemblage included at least 1 piece of lighting glass, 2 horseshoes, a leather shoe sole, 3 pieces of window glass, 18 nails, 3 pieces of brick, 6 fragments of iron fireplace hardware, an iron hinge, a carriage bolt, an iron hook, 8 creamware sherds, 2 porcelain sherds, 3 whiteware sherds, 2 ironstone, 2 redware sherds, 72 American gray stoneware pieces, 3 pieces of container glass, 2 faunal remains, a pipe stem, a pin, a female hygienic syringe (douche), an 1865 penny, 4 large iron fragments, a piece of cut copper, a piece of coal, a burnt stone, an unidentified object, and 2 prehistoric debitage fragments.
In the fall of 2009, undergraduate students from the University of Maryland, College Park, conducted limited excavation of four 1.524 X 1.524 m (5 X 5 ft) test units and one half-unit within a portion of the Riversdale garden. The overall goal was to evaluate the impact of an ongoing erosion problem on archaeological resources in the area, which was some 350 feet northeast of the mansion. All soils were removed from the excavation units according to natural stratigraphy using hand tools. Due to the students’ lack of experience, excavations proceeded slowly. Soils were then passed through hardware cloth and artifacts were removed and bagged according to their provenience. Architectural masonry (brick, mortar, and plaster) were present on the site in very large amounts. Because it lacked informative value and was too bulky to effectively curate, excavators retained only a sample of masonry from each unit to indicate its presence or absence. The remainder was discarded. All strata were photographed and mapped, and profiles were produced for each unit.
The UMD-CP students recovered 4,280 objects ranging in date from the early 19th century through the 20th century. These objects consisted mostly of architectural materials (53% or 2,247 objects), followed by glass, ceramics and other kitchen items (20% or 784 miscellaneous kitchen objects), agricultural and activity items (16 % or 665 items), and miscellaneous or unidentified objects (14% or 578 objects). They also unearthed the remains of a large garden wall erected around 1805 as well as the foundation of a brick structure built before 1830. This is likely one of two structures depicted in this area on an 1858 plan of Riversdale.
The various archeological projects conducted to date at the Riversdale Mansion (18PR390) demonstrate that Riversdale contains a diverse, abundant, and significant archeological record representing its historic occupation, use, and inhabitants. Not only are these resources likely to continue shedding light on the lifeways of the site’s Euro-American inhabitants, members of the prominent Calvert family, but information relevant to the study of the poorly documented enslaved inhabitants of Riverdale may be preserved as well. Examination of the interior of the structure in the 1980s helped to provide information on early drain systems and the original layout and structure of the basement of the manor house. Subsequent work on the exterior identified remains from a possible kitchen and landscape features that warrant additional investigation. Shovel testing of the property in the 1990s defined six activity areas that warrant further investigation. Archeological examination of the area where asphalt removal occurred identified the remains of 10 structures and over 100 features. And excavation in the late 1990s and first decade of the 21st century has provided significant detail on the timing of their construction and possible functions. These resources reflect the property's varied domestic, landscaping, and agricultural activities. Based on the results, the site (18PR390) has been determined eligible for the National Register of Historic Places as a contributing resource to Riversdale itself, which was already listed in the National Register. Numerous opportunities for further significant research exist at Riversdale.
External Reference Codes (Library ID Numbers): 00006657, 00006671, 00006760, 97001243, 95002602