Fossils of the Littleton Formation (Lower Devonian) of New Hampshire By A. J. BOUCOT and ROBERT ARNDT GEOLOGICAL SURVEY PROFESSIONAL PAPER 334-B UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1960 UNITED STATES DEPARTMENT OF THE INTERIOR FRED A. SEATON, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington 25, D.C. - Price 25 cents (paper cover) CONTENTS Page Page Abstract______ ______-_-_-_______--_-___-______--_-_ 41 Stratigraphy of the Littleton formation on Dalton Introduction __.____^-_-________________-.______.____ 41 Mountain. _ ______________________________________ 45 Systematic paleontology.______________-___-_-_--___- 46 Age of the Littleton formation_______________________ 41 Summary- _______--__--__---_---_------------------ 50 Geology of the Devonian fossil-collecting locality on Dal- Selected references--________________________________ 50 ton Mountain____________________________________ 43 Index _____________________________________________ 51 ILLUSTRATIONS [Plates 1-3 follow index] PLATES 1, 2. Brachiopods from the Littleton formation. 3. Brachiopods and other fossils from the Littleton formation. FIGURE 3. Index map showing quadrangles cited in text-_________________________________________________________ 42 4. Geologic map and cross-section of area adjacent to the Devonian fossil-collecting locality, Dalton Mountain, Whitefield quadrangle, N.H_______________________________________________________________________ 44 TABLES TABLE 1. Distribution of fauna from the Littleton formation of New Hampshire and the Moose River sandstone (upper part) of northern Maine-___-_-_-_-_-_________-_________________-___-__----_----------_----------- 43 in SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY FOSSILS OF THE LITTLETON FORMATION (LOWER DEVONIAN) OF NEW HAMPSHIRE BY A. J. BOUCOT AND EGBERT ARNDT ABSTRACT mens are slightly metamorphosed. The Littleton has Reexamination and study of fossils collected from 3 localities well-developed slaty cleavage and porphyroblasts of in New Hampshire show the presence of the brachiopods Amiriii- pyrite with pressure shadows of fibrous quartz (often genia and Eofler&naria cf. E. arciiata at 2 of the localities. in the beaks of the brachiopods). Metamorphism The evidence suggests a correlation of the containing strata renders the specific identification of the fossils difficult. with the Camden chert (Lower Devonian) of Tennessee. All The nearest fossiliferous beds of similar age are to the the fossils are from slightly metamorphosed (chlorite zone) strata of the Littleton formation in northern New Hampshire. northeast in Somerset County, Maine (upper part of Fossils from highly metamorphosed (sillimanite zone) rocks the Moose Kiver sandstone). correlated with the Littleton formation are determined to be of The following fossil-collecting localities are cited post-Early Ordovician age. Several thousand feet of unfossilif- in text: erous post-Silurian rocks, below the fossiliferous strata (Little- ton formation) in the Littleton quadrangle, are present in part 1. Pageau Farm (Tip Top Hill, loc. 8 of Billings and of the adjoining Whitefield quadrangle. The absence of these Cleaves, 1934), Littleton quadrangle, Grafton County, strata in part of the Whitefleld quadrangle may be due to X.H. USGS SD-3247. nondeposition or to erosion prior to deposition of strata of 2. Mormon Hill (loc. 11 of Billings and Cleaves, 1934), Camden age. Littleton quadrangle, Grafton County. N.H. 3. Mount Clough, Moosilauke quadrangle, Grafton INTRODUCTION County, N.H. 4. Dalton Mountain, Whitefield quadrangle, Coo:? County, The slightly metamorphosed fossiliferous beds of the X.H. USGS SD-3248. Two and three-quarters miles Littleton formation crop out in the Littleton, Moosi- northwest, of Whitefield, or one-half of a mile N. 10° lauke, and Whitefield quadrangles of northwestern E. of knob 2,000 feet elevation on northeast end of Dal­ New Hampshire (fig. 3). Devonian fossils were first ton Mountain. (See fig. 4.) reported from this area by F. H. Lahee (1912). A previous study of the fauna by Cleaves (Billings and AGE OF THE LITTLETON FORMATION Cleaves, 1934) concluded that the strata which yielded The fossils identified in the faunas collected from the fossils are of Oriskany age. Restudy of the fossils the Littleton formation and also the ones that are com­ available to Cleaves, plus those obtained from a new mon to the upper part of the Moose River sandstone are locality located by Arnclt in the Whitefield quadrangle shown on table 1. Inspection of table 1 indicates that (collected by Boucot and others) demonstrates that the the faunas from the Pageau Farm, Mormon Fill, and faunas are of Camden rather than of Oriskany age.1 Dalton Mountain are very similar and therefore are The locality in the Whitefield quadrangle was visited concluded to be of the same age. The forms common in the summer of 1949 by M. P. Billings, K. Fowler- to both the faunas of the Littleton formation pnd that Billings, and the authors. of the upper part of the Moose River sandstone sug­ The Littleton formation is the only formation in gests that these two units are of the same age. New Hampshire which has yielded generically identi­ The presence of Amplugemti in three of the above fiable fossils of Early Devonian age. All the speci- mentioned faunas indicates that they are to b° corre­ lated with the zone of Ampliigemn which elsewhere in 1 The Camden chert, in Boucot's opinion, is of Early Devonian age, as it is a correlative at least of part of the lower Emsian portion North America (Cloud, 1942, p. 77; Cooper, 1942, of the standard section for the Devonian in the Rhiiieland. Etirtixpirifer atJanticus of the Littleton formation and the Moose River sandstone chart) is thought to be restricted to strata of Onoiidaga (upper part) is very similar to Euryspirifer hercyniae (Giebel) which characterizes the lower Emsiari. age. In addition, the presence of highly convex speci- 41 42 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY FOSSILIFEROUS LOCALITIES 1 Pageau Farm 2 Mormon Hill 3 Mount Clough 4 Dalton Mountain 40 Miles FIGURE 3. Index map showing quadrangles cited in text. FOSSILS OF THE LITTLETON FORMATION, NEW HAMPSHIRE 43 TABLE 1. Distribution, of fauna from the Littleton formation of New Hampshire and the Moose River sandstone (upper part) of northern Maine Locality Fossil Species com­ Known stratigraphic range Dalton Pageau Mormon mon to MOOSP Mount Mountain Farm Hill River sand­ Clough stone (upper part) X Rhipidomelloides musculosa Solaris X X X X X X Euryspirifer cf. E. atlanticus V X X Late Early Devonian. X X X X Schuchertellal sp^ X X Silurian to Mississippian. X X X Ordovician to Mississippian. X X X X X X X Amphigenia cf. A. parva _ X X X Late Early Devonian. X X Brachiopod? X Unidentified pterineoid pelecypod X X X X mens of Eodevona-ria^ and spiriferoids similar to As recognized by Billings and Cleaves (1935, p. 534), Euryspinfer atlanticm are suggestive of a post-Oris- these specimens from Mount Clough were not suffi­ kany age since these forms have not previously been ciently diagnostic to date the enclosing rocks. They reported from strata of Oriskany age or older. assigned the rocks to the Littleton formation on the The faunules obtained from the Littleton formation basis of stratigraphic position and lithologic character. in the Littleton and Whitefield quadrangles occur in Because beds of massive gray sandstone at locality 2 structurally isolated synclines from which the strata are very poorly exposed, no attempt was made to deter­ cannot be traced directly into the adjacent highly meta­ mine their stratigraphic position within the sandy morphosed rocks with which they have been correlated. member. Cobbles of quartzite of the type fonnd in At Mount Clough (fig. 3, loc. 3) two specimens were the Albee formation are present in an outcrop of con­ obtained from the. metamorphic rocks correlated with glomerate that is approximately 250 feet west of local­ the immetamorphosed Littleton formation (Billings ity 2 (fig. 4). Their large size suggests that the con­ and Cleaves, 1935, p. 530-536). Both specimens were glomerate lies relatively close to the contact with the identified as brachiopocls by Cleaves, and the better Albee formation. The relation of bedding to cleavage specimen (pi. 3, fig. 26) as "tfph't'fer sp. inclet.'1 The indicates that a syncline lies to the southeast as at lo­ better specimen was probably a coarsely plicated cality 2. bivalve, but no basis for reliable phyletic assignment, much less a generic assignment, exists. It is Boucot's GEOLOGY OF THE DEVONIAN FOSSIL-COLLECTING LOCALITY ON DALTON MOUNTAIN opinion, after studying various faunas of early Paleo­ zoic age from the northern Appalachians, that the Fossils of Camden age are found in two exposures specimens probably are brachiopocls rather than pelecy- on the northwest limb of the Dalton Mountain subsidi­ pods, although this opinion cannot be proved on a mor­ ary syncline (fig. 4) (Billings, 1955). The rocks at phologic basis. If the specimens are brachiopocls or both exposures are slaty sandstone of the Littleton for­ pelecypods, it is probable that the containing beds are mation. At locality 1, which has yielded the most fos­ of post-Early Ordovician age. In Boucofs opinion sils and from which all the described material has the better specimen could be assigned to any coarsely come, the strata lie between 65 and 170 feet ab->ve the plicate brachiopod, including forms