700 ABSTRACTS OF PAPERS 



deposit. The argument depends on four assumptions : ( 1 ) The bog formed in 

 a kettle hole, not open to the sea; (2) the chanirecyparis stumps occur in place 

 from the bottom to the top of the deposits; (3) coastal subsidence is the only 

 theory competent to explain such a succession of stumps in place; (4) the 

 lower as well as the uppermost layers of the deposit are of recent date (that is, 

 formed within the last two or three thousand years). Evidence is presented 

 to show that the validity of each of the above assumptions must be questioned. 

 It is believed that the bog at Woods Hole affords no evidence either for or 

 against the theory of recent coastal subsidence. 



CONTRA-IMPOSED SHORELINES 

 BY CHARLES H. CLAPP * 



(Abstract) 



By the retrogression of a soft mantle covering hard rocks a shoreline, which 

 during an earlier portion of a marine cycle was a simple, cliffed, mature shore- 

 line, may be brought or "placed against" the underlying hard rocks. The re- 

 sulting shoreline will be irregular and in a very young stage. Such a shoreline 

 is analogous to the valley of a superimposed river and is called a "contra-im- 

 posed" shoreline. The development of contra-imposed shorelines near Victoria, 

 British Columbia, is described. 



PEAT DEPOSIT OF GEOLOGICAL INTEREST NEAR NEW HAVEN, CONNECTICUT 



BY CHARLES A. DAVIS 



{Abstract) 



Ordinary peat deposits in the glaciated regions of the United States are of 

 little interest to geologists compared with those of northern Europe, since they 

 are in most cases superposed on the late Wisconsin drift. They thus represent 

 a time too short to record many changes in climate or flora. 



Near New Haven, in the marshes of Quinnepiac River, is a deposit of excel- 

 lent brick clay, presumably of glacial origin, over which is superposed a peat 

 bed of varying thickness. The removal of the peat to work the clay bed by the 

 brickmakers has exposed large sections of peat which afford opportunities, 

 unusual in the United States, for studying the history of the beds. 



In a typical section at the brickyard near "Schutzer Park" the peat rests on 

 a thin bed of gravel or sand, on top of which is a forest soil bed, in which 

 there are stumps of trees whose roots penetrate the underlying gravel. Above 

 this woody stratum the peat shows flora changed gradually from forest to 

 fresh-water sedge marsh, then to brackish, and finally to salt marsh. The 

 stump-bearing layer is now several feet below the tide level of the undisturbed 

 marsh. The clay below the gravel has numerous woody roots much older than 

 those in the gravel. 



1 Introduced by D. W. Johnson. 



