54 GUIDE TO LOCALITIES. 



virginiana, Mya arenaria, Venus mercenaries and Pecten irra- 

 dians ; of these Mya arenaria is the only species now occurring 

 in abundance north of Cape Cod, the others being found only in 

 isolated " colonies." The size of the Mya and oyster shells was 

 found to be enormous — a valve of the latter, recorded by Upham, 

 having a thickness of one and one-half inches. A length of ten 

 inches is not uncommon among these shells. They are buried 

 again by the thousands just beneath the surface of this new-made 

 land, where any future digging will expose them. 



C. City point, South Boston (reached by electric cars from 

 Park square). — In the dredgings made to fill up the land for the 

 Marine park, many shells were brought up in the mud in 

 which they had been buried recently. Twenty-one species were 

 identified and recorded by Upham. 



The total number of species found in these three localities was 

 originally made twenty-five by Upham. The collections chiefly 

 from South Boston, of Mr. Warren Herman, have furnished 

 twenty-six more species, making a total of fifty-one species so far 

 recorded. Twenty-four of these are distinctly southern at the 

 present time, reaching their northward limit at Cape Cod or 

 Massachusetts bay, though some extend in isolated colonies 

 farther north. This indicates a period of warmer waters prece- 

 ding the present and succeeding the glacial episode. (For a com- 

 plete discussion see Upham '93.) 



Literature. 



{Palaeontology of eastern Massachusetts.) 



(Note : — While this bibliography aims to take account of all the impor- 

 tant contributions to the Paleontology of eastern Massachusetts, it 

 must necessarily be imperfect, on account of the very scattered distribu- 

 tion of the articles. Several minor papers, not dealing directly with the 

 palaeontological side of Massachusetts geology, purposely have been 

 omitted.) Consult also Hitchcock's Geology of Massachusetts. 



The most important papers are starred. 



1. Cambric. 



1834. Green, Jacob. Descriptions of some new North American Trilo- 

 bites. (Am.Journ. Sci., vol. 25, pp. 334-337.) Describes Para- 

 cloxkles harlani. 



