Map Unit Properties Table:

Unit Name Erosion Suitability for Cultural Mineral Geologic Age Features and Description Hazards Caves and Karst Habitat Recreation (Symbol) Resistance Infrastructure Resources Occurrence Significance

Carbonate sand Variable. Sand is Artifacts from Cliffs landward Gravel and sand formed by wave action along the ocean shore. Rare beaches of limited Calcium- Marine algae beaches are rare Beach less resistant to Low. Beach Safety issue at shipwrecks may of beaches may areal extent. Mapped at Sand Beach, Hunters Cove, Seal Harbor, Bracy Cove, and near the carbonate sand (seaweeds) in Beach activities. on the Atlantic (Hb) erosion than areas. high tide. wash onto contain sea Seawall picnic area on south . on Sand Beach. tidal zones. Coast north of larger clasts. beaches. caves. Cape Hatteras.

Artifacts may High due to tidal Salt water Limited areal Contains material Salt marsh Primarily clay, silt, and organic matter. Flat coastal grassland areas flooded by the sea at Low. Flooded by Safety issue at wash into flooding, roots, None. None. wetland extent. Partly eroded from (Hs) high tide. Limited areal extent. Relatively flat topography. the sea. high tide. marshes at high and topography. vegetation. flooded. surrounding areas. tide.

(Holocene) High due to Potential Sphagnum moss. Roads pass

QUATERNARY Freshwater wetland Organic-rich sediments that accumulate in flat, poorly-drained areas. May be open or Low. Wetland With burial, peat vegetation and None. American Indian None. Peat. Wetland through some (Hw) partly forested. areas. can become coal. topography. sites. vegetation. wetlands.

Low potential Traversed by Lichens and Talus Angular rock fragments. Accumulate at the base of steep hillsides and cliffs. Downslope Low. Landslide Safety issue. for artifacts. the road on the Example of mass High. None. None. moss. Limited (Ht) movement mainly by gravity. Limited areal extent. areas. Rocks may shift. Limited areal east side of wasting. areal extent. extent. Jordan Pond.

Emerged Marine Sediments Variable. High Wec: Pebbles, cobbles and boulders. Local concentrations deposited as beaches and bars Evidence of Coarse-grained seds (gravel) for Wec clasts. Cemeteries and Variable along ancient shorelines. Underlie roads, previous (Wec) Low for Wef, potential vegetation Hiking trails; Wef: Blanket deposits of silt, clay and sand deposited in quiet water environments on the buildings, golf Sand and gravel shorelines at Fine-grained seds which may slump Minor slumping. American Indian None. depending on roads; golfing;

) sea floor. course, and pits. elevations higher (Wef) on steep slopes and early settler gravel or silt campgrounds. Wed: Undifferentiated mixture of coarse-grained and fine-grained marine sediments that campgrounds. than current sea Undifferentiated sediments and stream sites. deposits. have been mixed by wave action. May include areas of Wec or Wef. level. (Wed) banks.

Wgo: Sand and gravel. Deposited in meltwater streams in front of the glacier margin. Forest Hill Glacial Stream Sediments Mapped in the southern part of Mount Desert Island south of Bubble Pond, at the north Wgo: Limited Riding stables; Cemetery (Wgd). Deposited during Outwash end of Upper Hadlock Pond, and south of Beech Mountain. Moderate, areal extent. Riparian trails; carriage Other potential melting of the (Wgo) Wgd: Sand and gravel. Deposited in deltas that formed along the paleo-shoreline and depending on Wgd: Underlies None. None. Gravel pits. vegetation; scrub roads; paved American Indian Wisconsin ice Delta (Undifferentiated) extended into the paleo-sea (1=older, 2=younger). Mapped in the southern part of Mount slope. buildings, roads, brush; forests. roads;

Wisconsin Glacial Stage and early settler sheet. (Wgd) Desert Island between Upper and Lower Hadlock Ponds, south of Jordan Ridge, and south trails. campgrounds. – QUATERNARY

sites. of Triad Pass.

Mixed rock debris ranging in size from clay to boulders. Deposited along the glacier margin High, unless Underlies Sand and gravel. Depositional End moraine Site of Jordan Manicured Jordan Pond and forms low ridges south of Jordan Pond, Echo Lake, and Long Pond on Mont Desert vegetation buildings, roads, None. None. Gravel pit south feature from (Wm) Pond House. lawns; forests. House. Island. Limited areal extent. removed. and trails. of Long Pond. glacial melting. (Pleistocene

High, unless Underlies roads, Cemeteries and Sand and gravel. Road touring; Depositional Till Heterogeneous mixture of clay, silt, sand, and larger clasts deposited directly from glacial Forest vegetation trails, and None. potential cultural None. Contains gravel sightseeing; feature from (Wt) ice. vegetation. removed. buildings. sites. pits. picnics. glacial melting.

REGIONAL UNCONFORMITY (Over 410 million years is missing from the geologic record between the Cadillac Mountain Intrusive Complex and the glacial till deposited by the Pleistocene glaciers.)

Dg: Miscellaneous small granite bodies. All contain biotite mica. Subscripts do not indicate Granite relative ages. (Dg)

Baker Island granite Hiking, Dg1: Pink, medium-grained granite with a faint northeasterly alignment of biotite grains. (Dg1) camping; Mapped on . Good, although Seawall to Bass High. Erosion Talus caves Talus blocks at sightseeing Dg2: Pink, fine-grained granite with a distinctive sugary texture. Contains abundant veins exposures are Exposures of Harbor granite increase where Potential rockfall Bass Harbor and possible. No base of sea cliffs along coast

(CMIC)* of coarser quartz and feldspar. Mapped from Seawall Point to Bass Harbor. limited. Units Quartz, alkali CMIC represent (Dg2) the units have associated with Baker Island limestone provide limited (lighthouses). Dg3: Pink, medium-grained granite occurring as dikes in the gabbro-diorite. Mapped in underlie roads, feldspar, biotite. shallow intrusive Pretty Marsh Harbor been cut by dikes steeper slopes. Lighthouses. (dissolution) habitat. Units are Limited

SILURIAN Pretty Marsh Harbor. buildings, trails, bodies. granite and fractures. caves. forested inland. exposures Dg4: Pink, medium-grained granite with scattered larger crystals of light lavender alkali and lighthouses. (Dg3) within park Complex feldspar. Mapped along Northeast Brook in Fresh Meadow. Northeast Brook boundaries.

Cadillac Mountain Intrusive Intrusive Mountain Cadillac granite Since the publication of the reference maps, these granitic units have been incorporated (Dg4) into the CMIC. Only Dg3 remains as a separate, mappable unit.

ACAD Geologic Resources Inventory Report 40 Unit Name Erosion Suitability for Cultural Mineral Geologic Age Features and Description Hazards Caves and Karst Habitat Recreation (Symbol) Resistance Infrastructure Resources Occurrence Significance

Pink and gray, medium-grained biotite granite containing pink or cream-colored potassium Talus caves feldspar and light gray plagioclase feldspar. Dsg1 is a fine-grained variety of Dsg. Dsg Good for most Building stones possible. No contains smaller mineral grains and a slightly different type of feldspar than Dcg. The black High. Erosion purposes (i.e. from Historic exposures along Quartz, alkali Sightseeing; Named for grains in Dsg are biotite mica, not hornblende as in Dcg. This is not an easy distinction to Deciduous and Somesville granite increases where buildings, roads, Potential rockfall Hall Quarry. coast so no sea feldspar, hiking. Limited exposures make. coniferous (Dsg, Dsg1) the unit has been campgrounds, associated with Potential early caves forming plagioclase, exposures adjacent to Somes forests grow to cut by dikes and and trails). Site of steeper slopes. settler and today. No biotite. Granite within park Sound, Mount Exposures along Route 102 south of Somesville show differences between Dsg and Dsg1. water’s edge. fractures. historic Hall American Indian limestone building stone. boundaries. Desert Island. Ledges of Dsg1 along the road north of Echo Lake show abundant phenocrysts (larger Quarry. sites. (dissolution) grains that are set in the fine-grained host rock). Farther south along the road, particularly caves. near the village of Hall Quarry, the granite is coarser grained (Dsg) and has no phenocrysts.

Thunder Hole notch. Emergent sea caves on Primary bedrock Pink to greenish-gray, coarse-grained granite. In contrast to Southwest Harbor granite Gorham High. Erosion on Mount Desert Carriage Roads. Cadillac Mountain (Dshg), the individual grains of translucent, gray, glassy-looking quartz and pink or gray Mountain Type locality is increases where Island. Underlies Potential rockfall Potential early Quartz, feldspar, granite feldspar are easily seen. The feldspar in Dcg is all pinkish perthite (greenish where fresh). (Cadillac Cliffs), Cadillac the unit has been buildings, roads, associated with settler and hornblende, (Dcg, Dcg1) The black minerals are primarily hornblende and occasionally biotite. Day Mountain, Mountain, Mount cut by dikes and trails, camp- steeper slopes. American Indian biotite.

(CMIC)* and Champlain Desert Island. fractures. grounds, and sites. Dcg1: Recrystallized zones within the Dcg. Mountain. No infrastructure. limestone (dissolution) caves. Suitable for most uses Light gray, fine-grained granite, commonly with a tan or pinkish hue. Contains both biotite High. Erosion Good. Underlies Cemeteries and Talus caves including Named for granite Southwest Harbor mica and hornblende. Mapped in the Southwest Harbor and Tremont areas and on increases where buildings, roads, Potential rockfall potential early possible. No hiking, exposed at No distinct granite Greening and Sutton Islands. Best exposures are along the shore at Southwest Harbor and the unit has been trails, camp- associated with settler and limestone picnicking, Southwest phenocrysts. (Dshg) near West Tremont. Inland exposures are not abundant. A magnifying glass helps to cut by dikes and grounds, and steeper slopes. American Indian (dissolution) Plants adapted to sightseeing, Harbor, Mount identify individual grains. The unit is similar to the granite found at Schoodic Point. fractures. infrastructure. sites. caves. rocky, treeless golfing, and Desert Island. mountain camping. summits. Forests Includes Gabbro: Dark gray, coarse-grained rock consisting of black pyroxene and/or hornblende grow to water’s historic carriage and gray plagioclase feldspar. edge. SILURIAN Complex Intrusive Mountain Cadillac Cemetaries. Great Head sea roads, Thunder Good for High. Increased Potential rockfall Potential early cave (opening Hole, sea cliffs, Gabbro-diorite Diorite: Lighter gray color due to the greater abundance of light gray plagioclase feldspar. buildings, roads, No distinct Mafic component erosion where associated with settler and along fractures). Acadia National and other (Dgd) trails, and other phenocrysts. to CMIC. cut by fractures. steeper slopes. American Indian No limestone Park lies in the popular visitor Good exposures on Route 3 west of Salsbury Cove (north side of Mount Desert Island), infrastructure. sites. caves transition zone attractions. Hulls Cove, Porcupine Islands and Bar Island northeast of Bar Harbor, and summit of of two eco- Great Head (east side of Mount Desert Island). regions: the Anemone sea northern boreal cave below forest (spruce- Unique zone Cemeteries. Schooner Head fir) and the Underlies part of No distinct bordering Angular blocks of dark country rock embedded in light gray granite bordering the contact High, but Potential early overlook eastern Shatter Zone Park Loop Road Potential rockfall phenocrysts or Cadillac Mtn. with Dcg to form a zone of intensely shattered country rock. Excellent exposures are found buffeted by surf settler and (opening along deciduous forest (Dsz) and city of Bar along sea cliffs. characteristic granite. Example at Otter Cliffs, Western Point, and Hunters Head. at high tide. American Indian fractures). No (i.e. oak, maple, Harbor. minerals. of cauldron sites. limestone beech). subsidence. (dissolution) caves.

SDcif: Blue-gray to light brown felsites and gray to brown dacite. Exposed only on Mount Desert Island. This unit has been reinterpred to be part of the CMIC. Felsites and flows

(SDcif) Suitable for SDcit: Gray crystal and lithic tuffs. Many of the beds appear water-laid, but ash falls and Good for most uses flows are present. Mapped mainly in the Big Heath area of southern Mount Desert Island High. Erosion Cemeteries. Talus caves Extrusive igneous Tuffs buildings, roads, including and on the Cranberry Islands. increases where Potential early possible. No rock related to (SDcit) trails, camp- Minor rockfall No distinct hiking, sight- the unit has been settler and limestone CMIC. Type grounds, and potential. phenocrysts. seeing, and SCcis: Interbedded volcanic rocks and contact metamorphosed siltstones and slates, cut by dikes and American Indian (dissolution) locality is Interbedded Volcanic other beach activities includes hornfels and gray, lavender, or cream-colored spotted slates. Mapped on the fractures. sites. caves. Cranberry Island. and Metasedimentary infrastructure. on Cranberry southern part of . rocks Islands.

Cranberry Island Series (SDcis) Since described by Gilman and others (1988), the Cranberry Island Series has been subdivided into 8 informal members (Seaman 2000).

ACAD Geologic Resources Inventory Report 41 Unit Name Erosion Suitability for Cultural Mineral Geologic Age Features and Description Hazards Caves and Karst Habitat Recreation (Symbol) Resistance Infrastructure Resources Occurrence Significance

Plants adapted to rocky, treeless mountain summits. Forests grow to water’s edge. The Ovens near Type locality is Siltstones and sandstones in beds a few centimeters (inches) thick. The beds weather to a High, but thin Salsbury Cove Acadia National Tourist Bar Harbor, tan, gray, or lavender color but are typically dark gray on a freshly broken surface. Strata siltstone beds are Contains the Minor rockfall 19th and early (open along Park lies in the activities in Bar Bar Harbor Formation . Records are gently tilted and undeformed along the shoreline at Bar Harbor, Maine. Graded less resistant to town of Bar potential along 20th century fractures). No None. transition zone Harbor, Maine, (SDbh) deposition in a bedding may be present in individual beds. At The Ovens and Ireson Hill, the unit is more erosion than Harbor, Maine. coast. development. limestone of two eco- and along the

SILURIAN marine flint-like, and bedding is difficult to distinguish. sandstone beds. (dissolution) regions: the coast. environment. caves. northern boreal forest (spruce- fir) and the eastern deciduous forest (i.e. oak, maple, beech).

REGIONAL UNCONFORMITY (Over 65 million years is missing between the Ellsworth Schist and the Bar Harbor Formation.)

Part of micro- Dark green or gray schist, often with a distinctive streaked appearance due to thin, lighter Talus caves

continent that colored layers of quartz and feldspar alternating with dark layers consisting mostly of the possible (open Vegetation Good. Underlies Potential Quartz and Hiking, attached to the mineral chlorite. The unit has undergone intense deformation compared to overlying units. along common to buildings, roads, Minor rockfall American Indian feldspar (light sightseeing. North American Ellsworth Schist (COe) Mapped primarily on the northwestern side and western edge of Mount Desert Island and High. fractures). No forests, coastal, trails, and other potential. and early settler bands); chlorite in Outside park craton. Deposited Bartlett Island. Minimal exposures within park boundaries. One of the better exposures is limestone and marsh infrastructure. sites. dark bands. boundaries. as mud on the sea

CAMBRIAN at the picnic area opposite the Acadia National Park information center on Thompson (dissolution) environments. floor over 500 Island. caves. million years ago.

REGIONAL UNCONFORMITY

Reference maps: 1) Gilman, R. A. and C. A. Chapman. 1988. Bedrock geology of Mount Desert Island. Bulletin 38. Maine Geological Survey, Augusta, Maine, USA (scale 1:50,000). 2) Lowell, T. V. and H. W. Borns, Jr. 1988. Surficial geology of Mount Desert Island. Bulletin 38. Maine Geological Survey, Augusta, Maine, USA (scale 1:50,000).

* Since publication of the reference maps, the Cadillac Mountain Intrusive Complex, Bar Harbor Formation, and the Cranberry Island Series have been reassigned to the Silurian and do not extend into the Devonian, as previously interpreted. Also, the Ellsworth Schist is entirely Cambrian.

ACAD Geologic Resources Inventory Report 42