H. W. Shimer — Post- Glacial History of Boston. 439 



" I find no plants or remains of plants such as now grow on 

 salt marshes or anywhere below high tide level. But what 

 species have entered into the formation of the peat I can not 

 determine beyond the presence of grasses and sedges, probably 

 both tops and roots, woody roots probably of some Ericaceous 

 plants, and fragments of wood. A large part, however, is 

 made up of much decomposed material now unrecognizable. 

 It has apparently, too, undergone considerable compression as 

 all the stems are flattened." 



Ostrea virginica. — This, our only species of oyster, is very 

 rare at Exeter Street, being represented by but three speci- 

 mens, the largest of which is only 85 mm long by 70 mm broad. 

 At Charles River this shell is exceedingly abundant including 

 both the long, narrow or so-called "current" form and 

 the short, broad " quiet-water " form. The most usual size 

 of the former is 230 mm in length and 55 mm in breadth ; 

 of the latter the length is 130 mm and the breadth 70 mm . At 

 Berkeley Street the very large current form is common at a 

 depth of 27 to 31 feet. A valve of one of these, an old 

 individual, with a length of 140 mm has a maximum thickness of 

 50 mm . At City Point the specimens are similar in size and 

 abundance to those from Charles River. Miss Bryant figures 

 one from here 265 mm by 80 mm . 



This oyster, as native, is now absent from Massachusetts 

 Bay ; during early colonial days it occurred only locally and 

 then, on account of the cold air at such depths as to be exposed 

 only at the low spring tides. A large oyster-bank was situated 

 at the mouth of the Charles River, another at the mouth of the 

 Mystic and probably one on the Noddles Island, now East 

 Boston, flats. 



That the large current forms flourished in Back Bay as late 

 as the middle of the seventeenth century is shown by the fol- 

 lowing quotations : 



" The Oisters be great ones in forme of a shoo home, some 

 be a foote long, these breed on certain bankes that are bare 

 every spring tide. This fish without the shell is so big that it 

 must admit of a devision before you can well get it into your 

 mouth."* .... "Towards the southwest in the middle of this 

 Bay" (i. e., Back Bay, at mouth of Charles River) " is a great 

 Oyster-banke "...." The Oyster-bankes " (referring to the 

 same) " doe barre out the bigger ships." 



In the first edition (1841) of the " Invertebrata of Massa- 

 chusetts," Dr. Gould says (p. 357) " old men relate that they 

 were accustomed to go up Mystic River and Charles River, 

 and gather oysters of great size, before it was the custom to 



* New England's Prospect, etc."; William Wood, London, 1634. Prince 

 Society Edition, 1865, pp. 39-44. 



