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Home , Fraser Lowland, Vashon Glaciation

J. E. ARMSTRONG Geological Survey of , Vancouver, B. C. DWIGHT R. CRANDELL U. S. Geological Survey, Denver, Colo. DONALD f. EASTERBROOK Western State College, Bellingham, Wash. }. B. NOBLE Washington State Division of Water Resources, Olympia, Wash.

Late Stratigraphy and

Chronology in Southwestern British

Columbia and Northwestern Washington

Abstract: Six geologic-climate units are proposed B.P. but did not reach the southern end until after for the sequence in southwestern 15,000 years B.P. The Vashon Stade of the Eraser and northwestern Washington. Glaciation began with this advance of Cordilleran They include two major units, the Olympia Inter- ice into the lowlands. It ended with the beginning glacmtion and the Eraser Glaciation, and four sub- of marine and glaciomarine conditions there, which divisions of the latter—the Evans Creek, Vashon, commenced in the southern Puget Lowland about and Sumas Stades, and the Everson Interstade. The 13,500 years B.P. and in the about Olympia Interglaciation is a nonglacial episode that 13,000 years B.P. The episode represented by the started at least 36,000 years B.P. and continued marine conditions is called the Everson Interstade until the advance of Cordilleran glacier ice during and lasted about 2000 years, during which the sea the Eraser Glaciation. During the Evans Creek contained much floating ice. The Interstade ended Stade, alpine glaciers formed in the mountains of when the land rose with respect to the sea level and British Columbia while forcing withdrawal of the sea and the disappearance nonglacial sediments were still being deposited in of floating ice in most of northwestern Washington the southern Puget Lowland. Further growth of and southwestern British Columbia; in the eastern glaciers in British Columbia resulted in the forma- part of the Eraser Lowland this event coincided tion of the . This ice entered with the advance of a valley glacier during the the northern end of the area after 25,000 years Sumas Stade.

CONTENTS Introduction and acknowledgments 321 northwestern Washington showing extent Previous work 323 of glaciation 322 Olympia Interglaciation 324 2. Late Pleistocene geologic-climate subdivisions Fraser Glaciation 326 and stratigraphic units in southwestern General statement 326 British Columbia and northwestern Wash- Evans Creek Stade 326 ington 324 Vashon Stade 327 Everson Interstade 327 Sumas Stade 329 Table References cited 329 1. Composite stratigraphic section of deposits in- cluded in Everson Interstade in eastern Figure half of Fraser Lowland, British Columbia 328 1. Map of southwestern British Columbia and

new geologic-climate units for the late Pleisto- INTRODUCTION AND cene in northwestern Washington and south- ACKNOWLEDGMENTS western British Columbia (Fig. 1). A new Stratigraphic studies between 1950 and 1963, formal name is proposed for the last major supplemented by more than 130 radiocarbon glaciation during which glaciers occupied the dates, have shown a need for defining several mountains and lowlands of this area. In the past

Geological Society of America Bulletin, v. 76, p. 321-330, 2 figs., March 1965 321 322 ARMSTRONG AND OTHERS—LATE PLEISTOCENE STRATIGRAPHY

Maximum extent of Cordil- lera glacier in Washington during Vasnon Stade,

Figure 1. Map of southwestern British Columbia and northwestern Washington showing extent of elaciation many writers have used the name Vashon below Vashon Drift in the southern Puget Glaciation to refer to this event. We now Lowland and southwestern British Columbia. propose to restrict the use of the name Vashon The Pleistocene sedimentation of this region to a stade. Two other stades and one interstade is one of alternate glacial and nonglacial deposi- within the last major glaciation are also named. tion. During each major glacial episode a Finally, a formal name is introduced for a non- Cordilleran glacier, originating in the moun- glacial interval represented by deposits directly tains of British Columbia, largely on the main- INTRODUCTION AND ACKNOWLEDGMENTS 323

land but partly on Vancouver Island, advanced the Washington State Division of Water Re- southward and southwestward into the Strait sources; Edmund Livingston and }. C. Fower- of Georgia, the Fraser Lowland, and the Puget aker of the British Columbia Water Investiga- Lowland. At its maximum the last Cordilleran tions B ranch; and S. C. Porter of the University ice sheet covered the Strait of Georgia and the of Washington. mountains of Vancouver Island. Southward the ice formed the Puget lobe which extended from PREVIOUS WORK the vicinity of Port Townsend to a point 15 The first recorded subdivision of the Pleisto- miles south of Olympia (Fig. 1) and terminated cene in southwestern British Columbia was laterally against the and made by Dawson (1887). He noted two tills the . In these mountains alpine separated by stratified sands and silts, but he glaciers were formed during an early stade of did not apply stratigraphic names to the de- the last major glaciation. These alpine glaciers posits. The earliest published subdivision of reached their maximum stands before the the Pleistocene of western Washington was advance of the Puget lobe and were in retreat presented by Willis (1898), who also recognized when the lobe reached the southern Puget two glaciations, Admiralty (older) and Vashon, Lowland. During a late stade of the last major separated by a nonglacial interval which he glaciation, after the Cordilleran glacier had re- named Puyallup. This sequence was subse- treated into the of British quently adopted with only minor modifica- Columbia, a valley glacier advanced at least 40 tions by most other workers in western Wash- miles into the Fraser Lowland. ington and southwestern British Columbia All the radiocarbon dates referred to in this (Bretz, 1913; Clapp, 1913; 1914; 1917; Bur- paper except where noted are published in wash, 1918; Johnston, 1923; Hansen and Radiocarbon—volumes 1, 3, 4, 5, and 6. Mackin, 1949; Sceva, 1957). In the preparation of this paper the authors A more complex sequence of geologic- made the following contributions: Armstrong climate units was subsequently established in acted as over-all co-ordinator, and he is re- the region. Mackin (Hansen and Mackin, 1949; sponsible for the British Columbia portions of Mackin and others, 1950) recognized three the geology, and for the definition of the glaciations separated by nonglacial intervals. Fraser Glaciation and Sumas Stade; Crandell Crandell and others (1958) established a is responsible for the definition of the Vashon sequence of four glaciations separated by non- and Evans Creek Stades and, along with Noble, glacial intervals, as follows: for the geology of the southern Puget Lowland Vashon Glaciation and definition of Olympia Interglaciation; Unnamed nonglacial interval Easterbrook is responsible for the definition of Salmon Springs Glaciation the Everson Interstade and for the geology of Puyallup Interglaciation the Fraser Lowland and northern Puget Low- Stuck Glaciation land in Washington. In addition to the authors' Alderton Interglaciation investigations recent field work by others has Orting Glaciation. contributed to the information contained Crandell and others found that deposits on herein, namely: J. G. Fyles and E. C. Halstead which Willis based his Admiralty Glaciation of the Geological Survey of Canada; D. R. are of different age from place to place, thus the Mullineaux, H. H. Waldron, and K. L. Walters name was not used in their sequence. of the U. S. Geological Survey; Dee Molenaar Likewise, detailed studies in the Fraser of Washington State Division of Water Re- Lowland of British Columbia by Armstrong sources; and W. L. Brown, consulting hydro- (Armstrong and Brown, 1953; 1954; Arm- geologist, Vancouver. All these workers have strong, 1956a; 1956b; 1957; 1960a; 1960b; read the paper and are in general agreement unpub. inf.) and on Vancouver Island (Fyles with the names and usages proposed; however, 1960a; 1960b; 1963; Halstead, 1963) led to the authors assume full responsibility for the the discovery of a far more complex succession definitions of the proposed geologic-climate of climatic events than had been formerly units. The following workers have also read the recognized (Fig. 2). Armstrong established the paper and concur with the above: S. F. Learning following stratigraphic sequence in the Fraser of the Geological Survey of Canada; H. W. Lowland : Anderson, A. A. Garrett, and J. E. Luzier of Sumas Drift the U. S. Geological Survey; R. H. Russell of Capilano sediments 324 ARMSTRONG AND OTHERS—LATE PLEISTOCENE STRATIGRAPHY

Surrey Drift Quadra sediments Quadra sediments Dash wood Drift Semiamu Drift Mapleguard sediments. Nonglacial sediments The present paper is concerned with the last At least two older unnamed drifts sepa- major glaciation, which has heretofore been rated by nonglacial sediments occur in referred to as Vashon, and with the nonglacial the lower part of the sequence. interval preceding the Vashon.

FRASER LOWLAND SOUTHERN ABSOLUTE EAST COASTAL LOWLANDS PUGET GEOLOGIC-CLIMATE TIME BRITISH WASHINGTON UNITS THOUSANDS COLUMBIA VANCOUVER LOWLAND ISLAND Grand ell (1963) of YEARS Armstrong (1956 et sw Easterbrook(1963: Molenaar&Garling B.R and unpublished ms.) Fyles (1963) (1963 1— ""- .. 10 — ^\ Drifl ^-> Or if! "-> STADE-.^1" ^- ' ^"' 11 — srtimen'ts What com Bellmgham

EVERSON deposits Ca |(ano d'ifl 12 — INTER STADE Newton sediments Demmg Z stony clay O 13 — Clover dale Kulshan sediments glacioma.ine h- ~~~~~~~~~— u 14 — — - ———.

/ 17 ~ 0. ^

/ y 0 O "^- .^ EVANS 19 — f«ans Creek /CREEK ta 01 Drift /STADE' J -• ' / 21 — E E / X^ / • 0 Ul 1

/ 23 — / ? /

0 25 — " "

Z 29 —

< Ouad.a sedirnents Quadra sediments Kilsap Formation 33 — £L £ > 36 —

0

SALMON Semiamu Drift 9 SPRINGS! ) (age unknown) GLACIAT1ON Dasltvvood Drift Oritt tage unknown) Figure 2. Late Pleistocene geologic-climate subdivisions and stratigraphic units in south- western British Columbia and northwestern Washington

In the western part of the Fraser Lowland Armstrong and Brown (1953) referred in- OLYMPIA INTERGLACIATION formally to the till sheet at the surface as the The climatic episode immediately preceding Surrey till. They found that in places the de- the last major glaciation, and represented by posits Armstrong now believes to belong to the nonglacial strata lying beneath Vashon Drift is Vashon Stade consist of the "Surrey till" sheet herein named the Olympia Interglaciation. and one or more earlier till sheets separated by During this interval ice was absent from the glaciofluvial and glaciolacustrine deposits. lowlands of northwestern Washington and Fyles established the following stratigraphic southwestern British Columbia. sequence on Vancouver Island: Physical evidence for this episode Capilano sediments exists at many places in the southern Puget Vashon Drift Lowland in Washington, and on both sides of OLYMPIA INTERGLACIATION 325 the Strait of Georgia in British Columbia. In Lowland was that of shallow lakes, swamps, and British Columbia deposits of this episode have flood plains in the drainages of the ancestral been referred to as "Quadra sediments" Nisqually and Puyallup rivers. Some forest (Armstrong and Brown, 1953; Fyles, 1963), cover existed. A cool and moist climate is in- although, as outlined further on, the "Quadra" ferred from a predominance of and of Fyles may include some pre-Olympia de- pollen in deposits of Olympia age at posits. (Mullineaux and Waldron, in press). Deposits of the Olympia Interglaciation are The fluvial and lacustrine deposits are over- typically exposed along the shores of Puget lain by Vashon Drift and are underlain by Sound between Olympia and Seattle, and the glacial deposits that are probably correlative type section of the interglaciation is designated with the Salmon Springs Drift. as a sea cliff 0.6 mile southeast of West Point at The basal contact is apparently conformable Seattle. At this locality, nonglacial fluvial and at several localities near Olympia, but an ero- lacustrine clay, silt, and sand about 70 feet sional unconformity exists between Salmon thick underlie proglacial lacustrine silt and clay Springs (?) and the nonglacial deposits on the of Vashon age (Mullineaux and Waldron, in west side of Colvos Passage. press). Three radiocarbon dates on organic "Quadra sediments" are widespread on the matter obtained from these deposits range from lowlands on both sides of the Strait of Georgia, 18,100 ± 700 (W-1186) to 22,400 ± 800 on the islands in the strait, and within some of (W-1091) years. Radiocarbon dates on deposits the valleys extending into the adjoining moun- of the Olympia Interglaciation elsewhere at tainous regions. In all places they unconforma- Seattle range from 15,000 ± 400 years bly underlie Vashon Drift or its equivalent (W-1227) to 24,300 ± 700 years (W-1388) Surrey Drift. The name "Quadra" was first (Mullineaux and Waldron, in press; D. R. used by Armstrong and Brown (1953) for Mullineaux, oral communication, 1964). subtill sediments forming prominent cliffs on Similar, but probably in part older, non- Point Grey in Vancouver. In this section the glacial deposits are exposed in sea cliffs adjacent "Quadra" strata consist of about 50 feet of silt, to between Tacoma and Olympia, clay, sand, and peat overlain apparently con- along Colvos Passage, and on the south shore of formably by up to 150 feet of white sand and Sinclair Inlet. Published radiocarbon dates on minor gravel. Johnston (1923) designated the peats from these deposits range from 27,900 + basal 50 feet the "Point Grey Formation." 800 years (U.W.-7) to 34,700 + 1,100 (U.W.- Although the base of the section is below sea 20), however, preliminary reruns (U.W.-1964) level and unobservable, Armstrong and Brown on some of these peats give older radiocarbon regarded the "Quadra" as intertill sediments on dates (J. B. Noble, personal written com- evidence obtained from drill holes 1-2 miles munication). A date of 26,850 + 1,700 years east of the seacliffs and from exposures outside (1-1111, Easterbrook, unpub.) has been ob- of the type section. Three radiocarbon analyses tained from wood in a peat bed beneath Vashon of peat from near the base of the Point Grey Drift on . seacliffs yielded dates ranging from 24,400 + The nonglacial deposits along Colvos Passage 900 years (L-502) to 25,000 + 600 years and at Sinclair Inlet were included in the Kitsap (GSC-109). Radiocarbon dates obtained on Clay Member of the Orting Gravel by Sceva organic material contained in "Quadra sedi- (1957). The Orting Gravel, originally named ments" at three other localities in the western by Willis (1898), is now regarded as of early part of the Fraser Lowland range from 26,450 ± Pleistocene age (Crandell and others, 1958); 520 years (GSC-124) to 36,200 ± 500 years thus, it appears that Sceva's correlation was (GSC-93 rerun, Armstrong, unpub.). The incorrect, and that the unit he called Orting oldest date is on peat obtained from the base of Gravel in the central part of the lowland is at a section and lying directly on till. least in part Salmon Springs Drift. Recognition On Vancouver Island Fyles (1963) applied of this led J. B. Noble and E. F. Wallace (un- the name "Quadra" to intertill sediments on pub. ms.) and Molenaar and Garling (1963) to the basis of the remarkable similarity of the give the name Kitsap Formation to Sceva's widespread white sands to Armstrong and Kitsap Clay Member, and this usage is fol- Brown's Point Grey "Quadra sediments." He lowed here. described them as follows (p. 19):' 'The Quadra The depositional environment during the sediments of the area are nonglacial strata lying Olympia Interglaciation in the southern Puget between the Dash wood Drift and Vashon 326 ARMSTRONG AND OTHERS-LATE PLEISTOCENE STRATIGRAPHY

Drift and comprising (1) a lower unit of of southwestern British Columbia and western marine 'clay' and stony 'clay'. .. .; (2) a middle Washington is here named the Fraser Glacia- unit of -bearing silt, and sand; and tion from the Fraser Lowland (Fig. 1) of (3) a thick upper unit of white sand with local British Columbia where deposits attributed to gravels and plant-bearing silts." These may this episode are typically exposed. The Fraser have a total thickness of more than 300 feet. Glaciation includes what has previously been Units 2 and 3 of Fyles' "Quadra sediments" are referred to as an early alpine phase of the equivalent to Armstrong and Browns' "Quadra Vashon Glaciation (Crandell, 1963), Vashon sediments" in the Eraser Lowland. Unit 1, Glaciation (Willis, 1898), and Sumas Glaciation including coldwater marine and glaciomarine (Armstrong, 1957). These three glacial episodes deposits, has not been recognized on the main- are now given the rank of stades (Fig. 2). The land. It represents a transition from glaciation Vashon and Sumas Stades are separated by an to interglaciation and on the basis of four radio- essentially nonglacial episode here named the carbon dates is appreciably older than the non- Everson Interstade. marine "Quadra" deposits. The Fraser Glaciation probably represents Wood and peat collected from units 2 and 3 the same geologic-climate episode as the of Fyles' "Quadra sediments" at various locali- "classical" Wisconsin Glaciation of the mid- ties along the east coast of Vancouver Island western (Flint, 1957). from Campbell River to Victoria (140 miles) have yielded 18 radiocarbon dates ranging from Evans Creel^ Slade 19,150 + 250 years (GSC-195, Halstead, Willis (1898) believed that during the unpub.) to 35,400 ± 400 years (GSC-202, Vashon glaciers spread into the Puget Lowland rerun on L-455, Fyles, unpub). from the Cascade Range and Olympic Moun- Pollen and plant studies have been made by tains and became confluent there with an ice J. Terasmae (Fyles, 1963; unpub. communica- sheet from the Coast Mountains of British tion) of the Geological Survey of Canada on Columbia. Although he specifically applied the organic materials collected from the "Quadra name Vashon to drift of the Puget lobe, he in- sediments" on both Vancouver Island and the cluded in the same glacial episode the expansion mainland of British Columbia. Characteristic of the contemporaneous glaciers from the presence of pine, spruce, and Abies (), Cascades and Mount Rainier. Subsequent paucity of western hemlock, and absence oi studies have shown, however, that alpine Douglas fir point definitely to a cooler climate glaciers on the western side of the Cascade than now for most of the "Quadra"; however, Range had reached their maximum extents the record is very incomplete. and had retreated before the Puget lobe of the The time bracketed by known deposits of Cordilleran ice sheet reached its maximum the Olympic Interglaciation may be sum- stand (Gary and Carlston, 1937; Mackin, marized as follows: In the southern Puget 194la; 1941 b; Crandell, 1963). Lowland it extended from at least 35,000 years The Evans Creek Drift was named by B.P. to 15,000 years B.P., or 20,000 years in Crandell (1963) from drift deposited by an total; in the eastern coastal lowlands of Van- alpine glacier in the Carbon River valley north- couver Island from at least 35,000 years B.P. west of Mount Rainier; this glacier formed a to 19,000 years B.P. or about 16,000 years in terminal near the mouth of Evans total; and in the Fraser Lowland from at least Creek, a tributary of the Carbon (Fig. 1). The 36,000 years B.P. to 24,500 years B.P. or moraine is directly overlain by lacustrine sedi- 11,500 years in total. These are all minimum ments deposited in a Vashon in periods of time as the lower time limit of the the Carbon River valley that was dammed by Olympia Interglaciation has not been estab- the Puget lobe at its maximum stand. Crandell lished and may be represented by radiocarbon inferred that when the Puget lobe formed this dates older than about 37,000 years B.P. lake, the alpine glacier in the Carbon River valley had retreated far upvalley, and was not FRASER GLACIATION contributing coars; outwash to the lake. The Evans Creek Stade is defined as the General Statement climatic episode early in the Fraser Glaciation The last major glaciation during which during which large alpine glaciers formed and glaciers occupied the mountains and lowlands reached their maximum extents and deposited FRASER GLACIATION 327 drift in the mountains of western Washington climax terminated about 15 miles south of adjoining the southern Puget Lowland. This Olympia. Following this maximum stand, the growth was probably contemporaneous with lobe retreated from the southern Puget Low- initial development of the Cordilleran ice sheet land and permitted marine water to enter the in the mountains of the mainland of western area. Marine conditions began in the Seattle British Columbia. Continued expansion of area some time prior to about 13,500 years ago alpine glaciers in British Columbia apparently (Rigg and Gould, 1957). The sea occupied the resulted in ice sheet formation; whereas, to the Strait of Georgia area and bordering lowlands south, growth of alpine glaciers was interrupted about 13,000 years B.P. before the ice sheet phase was reached, and in- During the Vashon Stade the Cordilleran dividual glaciers began to retreat. glacier covered the Coast Mountains near the city of Vancouver to altitudes of at least 6000 Vashon Stade feet, and on Vancouver Island it extended to at The Vashon Glaciation, here named Vashon least 5500 feet. Further north in the Coast Stade, was originally named from Vashon Mountains the ice probably reached altitudes Island in Puget Sound (Willis, 1898), where till of 7500 feet or more (Davis and Mathews, and glaciofluvial deposits formed during the 1944). Proceeding south from the Canada- most recent advance and recession of the Puget United States border the ice sheet progressively lobe are typically exposed. Other workers thinned from about 5500 feet to about 3000 subsequently extended the name Vashon to in- feet in the Seattle area (Mackin and others, clude deposits attributed to the last major 1950). advance of Cordilleran ice throughout the On Vashon Island and in much of the area Puget Lowland of Washington, the Fraser under discussion, the Vashon Stade is repre- Lowland of British Columbia, and the lowlands sented by glaciofluvial sediments and what bordering the east and south coasts of Van- appears to be a single till sheet, varying in couver Island. The Vashon Stade is here denned thickness from less than 5 to 100 feet. In the as the last major climatic episode during which southern Puget Lowland the till forms the sur- drift was deposited by continental ice originat- face deposit on upland areas and extends down ing in the mountains of the mainland of British valley walls to and probably beneath the allu- Columbia and occupying the lowlands of vium on the valley floors. In the northern southwestern British Columbia and north- Puget Lowland, the Fraser Lowland, and the western Washington. The Stade began with the coastal lowlands on the east side of Vancouver advance of Cordilleran ice into these lowlands Island the same distribution of Vashon till or and ended with the beginning of marine and its stratigraphic equivalent may be observed in glaciomarine conditions in them. many places; however in parts of these areas, Radiocarbon analyses of wood and peat from particularly in the Fraser Lowland, the Vashon nonglacial deposits beneath the Vashon Drift deposits are overlain by thick glaciomarine and or equivalent drift indicate that the Cordilleran marine deposits of the Everson Interstade. glacier entered the north end of the Strait of Georgia after 25,000 years B.P., the Fraser Everson Interstade Lowland after 24,500 years B.P., and the south- Glaciomarine, marine, and related deposits east coast of Vancouver Island after 19,000 accumulated in the coastal lowlands of north- years B.P. These are only limiting dates, how- western Washington and southwestern British ever, and the time when the ice sheet entered Columbia during the retreat of the Vashon ice. the lowlands is not yet established. Between The episode represented by these deposits is about 15,000 and 25,000 years B.P. Evans here named the Everson Interstade and began Creek glaciers probably occupied the moun- with the invasion of the lowlands by the sea tains, while nonglacial sediments were still and apparently ended in the eastern half of the geing deposited in the Puget Lowland. Radio- Fraser Lowland during the advance of Sumas carbon dates on wood from these nonglacial ice. Elsewhere it ended with the withdrawal of deposits at Seattle (Mullineaux and Waldron, the sea from most of the area and the disap- in press) indicate that the Cordilleran ice did pearance of floating ice. The relative position not push far southward into the Puget Lowland of the land and sea fluctuated from 600 feet or until about 15,000 years B.P. The Puget lobe more above sea level, to present sea level or advanced across the Seattle area and at its below. During this period of deposition glacier 328 ARMSTRONG AND OTHERS—LATE PLEISTOCENE STRATIGRAPHY ice did not cover the lowlands, although floating represented by a more complex sequence of ice was present during part or most of it. deposits (Armstrong, 1956a; 1956b; 1957; This ice was chiefly in the form of bergs, but 1960a; 1960b; unpub. inf.), although fossilifer- probably also included shelf ice or sea ice or ous glaciomarine stony clays and stony silts both. are the most characteristic facies. A composite Physical evidence for this interstade is best section of these deposits, possibly oversimpli- exhibited in the Fraser Lowland of British fied, is shown in Table 1. Columbia and Washington. In this area the Radiocarbon dates on shells and wood col- deposits reach a maximum thickness of at least lected from the lithologic units of Table 1 are 550 feet and include interbedded fossiliferous as follows: shells from marine clay of unit 2 stony clay, stony silt and till-like mixtures, yielded a radiocarbon age of 11,930 ± 190 marine clay, deltaic sand and gravel (partly marine); fluvial and lacustrine clay, silt, sand, TABLE 1. COMPOSITE STRATIGRAPHIC SECTION OF and gravel; and peat. DEPOSITS INCLUDED IN EVERSOX INTERSTADE IN The name of the Interstade is derived from EASTERN HALF OF FRASER LOWLAND, BRITISH the town of Everson on the , COLUMBIA about 7 miles downstream from outcrops on the south bank of the river that are typical of the Average Interstade and that are here designated as the thickness type section (NE % sec. 34, T. 39 N., R. 4 E.). Lithologic unit (feet) At these exposures, two fossiliferous glacio- marine deposits are separated by fluvial sand. Top of section: Sumas Drift From bottom to top, Easterbrook (1963) 6. Glaciomarine and minor marine sedi- named these the "Kulshan glaciomarine drift," ments, mainly pebbly silty clay 200 the "Deming sand," and the "Bellingham 5. Deltaic sand and gravel 50 glaciomarine drift" (Fig. 2). The "Kulshan 4. Glaciomarine and minor marine sedi- ments, mainly pebbly silty clay 75 glaciomarine drift" is 25 feet or more thick 3. Deltaic sand and gravel 75 and consists of till-like pebbly clay that con- 2. Marine sediments, mainly clay, silty clay, tains marine fossils. Pebble lithology and heavy- and silt ' 100 mineral analyses indicate a British Columbia I. Deltaic sand and gravel 50 provenance. The "Deming sand" is about 30 feet thick and contains a peat bed near its Bottom of section: Surrey Drift base. The sand represents a period of emer- gence, and its lithology suggests a local prov- enance. The "Bellingham glaciomarine drift" years (GSC-168); three specimens of wood is 70 feet thick and consists of a till-like glacio- from glaciomarine pebbly silty clays of units marine pebbly clay. Marine shells in it indicate 4 and 6 yielded radiocarbon ages ranging from a return to marine conditions and its lithology 10,950 ± 200 years (L-331C) to 11,700 ± 150 indicates a source in British Columbia. years (L-331B); and shells from glaciomarine Radiocarbon dates on organic material from pebbly silty clay of unit 6 yielded a radiocarbon deposits of the Everson Interstade in Washing- age of 11,680 + 180 years (GSC-186; Arm- ton have a range of about 1500 years. Shells strong, unpub.). from near the top of the "Kulshan glacio- Units 4 and 6 consist mainly of glaciomarine marine drift" have an age of 11,660 + 350 sediments and were named "Whatcom glacio- years (W-996). Wood from the peat bed in the marine deposits" (Armstrong, 1957; 1960a; "Deming sand" at the Nooksack River locality 1960b). Unit 2 consists mainly of marine de- has been dated as 11,640 ± 275 years (W-940), posits and was named "Cloverdale sediments" and at another locality, peat from immediately (Armstrong, 1957; 1960a; 1960b). These terms beneath the "Bellingham glaciomarine drift" essentially designate facies. Although only has an age of 12,090 ± 350 years (W-984). three deposits of deltaic sand and gravel (units Wood samples from the "Bellmgham glacio- 1, 3, and 5) are shown in the composite section, marine drift" have ages of 11,800 + 400 years there probably are several more that have not (1-1037) and 10,370 years (1-1035) (Easter- been differentiated due to their lenticular brook 1963). nature. In the eastern half of the Fraser Lowland in In the western half of the Fraser Lowland British Columbia, the Everson Interstade is of British Columbia the Everson Interstade is FRASER GLACIATION 329

represented by 5-50 feet of glaciomarine and glaciomarine deposits of Everson age, thus in- marine sediments that were named "Newton dicating a probable readvance of Cordilleran stony clay" by Armstrong and Brown (1953; ice. A perhaps less likely alternative, which 1954). Six radiocarbon dates on shells from might not require a readvance of the Cordil- these deposits ranged from 11,900 + 300 years leran glacier, is that the Sumas till merely rep- (L-391C) to 12,800 ± 175 years (1-248). These resents the grounding of drift-bearing shelf ice dates suggest that the "Newton stony clay" throughout the area (Easterbrook, 1963). may be a little older than the "Whatcom" and The name of the stade is derived from the "Cloverdale sediments," although Armstrong town of Sumas on the United States-Canada believes that they were deposited during the border in the eastern part of the Fraser Low- same general episode. land. A 150-foot section of Sumas Drift is des- The dates cited indicate that the duration ignated the type section and consists of advance of the Everson Interstade probably was at outwash overlain by till, and is exposed in a least 2000 years in the Fraser Lowland, ex- gravel pit a few hundred yards west of the town tending from about 13,000 to 11,000 years B.P. on the Canadian side of the border. Northwest Lithologically similar glaciomarine and ma- of the town recessional outwash rests on Sumas rine sediments believed to have been deposited till. during the Everson Interstade have been At many places north and south of the Trans- recognized over an area of more than 7000 Canada Highway (No. 1) and west of the square miles, extending from Whidbey Island in village of Abbotsford, Sumas till lies directly on Puget Sound northwest to Campbell River on glaciomarine deposits of the Everson Interstade. Vancouver Island. Radiocarbon dates on these Radiocarbon dates of 11,500 + 1,100 years deposits at 14 places range from 10,690 + 180 (L-221D) and 11,000 + 900 years (L-221E) years (GSO185) to 12,500 ± 450 years have been obtained on wood found 1 or 2 feet (GSC-9). above the base of Sumas till at two localities where the till overlies glaciomarine stony silty Sumas Stade clay. These dates from wood in the till and During the final stages of emergence in the those obtained from underlying sediments sug- Fraser Lowland, a valley glacier occupied the gest the advance of Sumas ice began about eastern part of the lowland and deposited drift. 11,000 years B.P. No conclusive evidence has The climatic episode represented by these de- yet been found that indicates the time when the posits is named the Sumas Stade. The Sumas Sumas ice disappeared. However, Borden glacier is believed by Armstrong to have been (1957) has shown that Indians occupied the a lobe of the Corddleran glacier. In an area valley at Yale (Fig. 1) 9000 + 150 covering 250 square miles Sumas Drift overlies years (S-113) ago.

REFERENCES CITED Armstrong, J. E., 1956a, Surficial geology of the Vancouver area, British Columbia: Canada Geol. Survey Paper 55-40, 16 p. 1956b, Mankato drift in the lower of British Columbia: Geol. Soc. America Bull., v. 67, p. 1666-1668 1957, Surficial geology of the New Westminster map-area, British Columbia: Canada Geol. Survey Paper 57-5, 25 p. 1960a, Surficial geology of the Sumas map-area, British Columbia: Canada Geol. Survey Paper 59-9, 27 p. 1960b, Surficial geology of the map-area, British Columbia: Canada Geol. Survey Prelim. Map 53-1959 Armstrong, J. E., and Brown, W. L., 1953, Ground-water resources of Surrey Municipality, British Columbia: Canada Geol. Survey Water-Supply Paper 322, 48 p. 1954, Late Wisconsin marine drift and associated sediments of the lower Fraser Valley, British Columbia, Canada: Geol. Soc. America Bull., v. 65, p. 349-364 Borden, C. E., 1957, An early site in the , British Columbia: Canada Natl. Mus. Bull. 162, p. 101-119 Bretz, J H., 1913, Glaciation of the : Wash. Geol. Survey Bull. 8, 244 p. 330 ARMSTRONG AND OTHERS—LATE PLEISTOCENE STRATIGRAPHY

Burwash, E. M. J., 1918, Geology of Vancouver and vicinity: Univ. Chicago Press, 106 p. Gary, A. S., and Carlston, C. N., 1937, Notes on Vashon glaciation of the South Fork of the Skyomish River valley, Washington: Northwest Sci., v. 11, p. 61-62 Clapp, C. H., 1913, Geology of the Victoria and Saanich map-areas, Vancouver Island, British Columbia: Canada Geol. Survey Memoir 36, 143 p. 1914, Geology of the Nanaimo map-area, British Columbia: Canada Geol. Survey Memoir 51, 135 p. 1917, Sooke and Duncan map-areas, Vancouver Island: Canada Geol. Survey Memoir 96, 445 p. Crandell, D. R., 1963, Surficial geology and geomorphology of the Lake Tapps quadrangle, Washington: U.S. Geol. Survey Prof. Paper 388-A, 84 p. Crandell, D. R., Mullineaux, D. R., and Waldron, H. H., 1958, Pleistocene sequence in southeastern part of the Puget Sound lowland, Washington: Am. Jour. Sci., v. 256, p. 384-397 Davis, N. F. G., and Mathews, W. H., 1944, Four phases of glaciation with illustrations from south- western British Columbia: Jour. Geology, v. 52, p. 403-413 Dawson, G. M., 1887, Report on a geological examination of the northern part of Vancouver Island and adjacent coasts: Canada Geol. Survey Ann. Rept. 1886, v. 2, pt. B, 107 p. Easterbrook, D. J., 1963, Late Pleistocene glacial events and relative sea level changes in northern Puget Lowland, Washington: Geol. Soc. America Bull., v. 74, p. 1465-1484 Flint, R. F., 1957, Glacial and Pleistocene geology: New York, John Wiley and Sons, 553 p. Fyles, J. G., 1960a, Surficial geology, Oyster River map-area, British Colombia: Canada Geol. Survey Prelim. Map 49-1959 1960b, Surficial geology, Courtenay map-area, British Columbia: Canada Geol. Survey Prelim. Map 32-1960 1963, Surficial geology of Home Lake and Parksville map-areas, Vancouver Island, British Columbia: Canada Geol. Survey Memoir 318, 142 p. Halstead, E. C., 1963, Surficial geology, Nanaimo map-area, British Columbia: Canada Geol. Survey Prelim. Map 27-1963 Hansen, H. P., and Mackin, J. H., 1949, A pre-Wisconsin forest succession in the Puget lowland, Washing- ton: Am. Jour. Sci., v. 247, p. 833-855 Johnston, W. A., 1923, Geology of the FVaser River delta map-area: Canada Geol. Survey Memoir 135, 87 p. Mackin, J. H., 1941a, A geologic interpretation of the failure of the Cedar reservoir, Washington: Univ. Washington, Eng. Expt. Sta. Bull., Ser. no. 107, 30 p. 194lb, Glacial geology of the Snoqualmie-Cedar area, Washington: Jour. Geology, v. 49, no. 5, p. 449-481 Mackin, J. H., Mullineaux, D. R., and Stark, W. J., 1950, Glacial geology of Seattle. The trend in engineering: Univ. Washington, v. 2, no. 4, p. 19-21 Molenaar, Dee, and Garling, M. E., 1963, Water resources and geology of Kitsap Peninsula and certain adjacent islands, plates 1 and 2: Washington Div. Water Res., Water-Supply Bull. 18, map supplement Mullineaux, D. R., and Waldron, H. H., in press, Significance of the Lawton Clay in the late Pleistocene history of the Seattle area, Washington: U. S. Geol. Survey Bull. Rigg, G. B., and Gould, N. R., 1957, Age of Glacier Peak eruption and chronology of post-glacial peat deposits in Washington and surrounding areas: Am. Jour. Sci., v. 255, p. 341-363 Sceva, J. E., 1957, Geology and ground-water resources of Kitsap County, Washington: U.S. Geol. Survey Water-Supply Paper 1413, 178 p. Willis, Bailey, 1898, Drift phenomena of Puget Sound: Geol. Soc. America Bull, v. 9, p. 111-162

MANUSCRIPT RECEIVED BY THE SOCIETY JULY 13, 1964 PUBLISHED WITH THE PERMISSION OF THE DIRECTOR, GEOLOGICAL SURVEY OF CANADA, THE DIRECTOR, U. S. GEOLOGICAL SURVEY, THE DIRECTOR, WASHINGTON STATE DEPARTMENT OF CONSERVATION