THE NAUTILUS. 11 



Planorhis parvus Say. These Taried in size as much as did the 

 shells of Valvata tricarinata Say, and were about as abundant. 



Pisidium variable Prime. This species was very rare. Usually 

 the valves were separated, only occasionally were they found united. 



Whether or not these forms still inhabit this place I am not pre- 

 pared to say. Though I have not been able to find any living indi- 

 viduals, further search may yet reveal them, 



I desire to acknowledge the assistance of Mr. L. P. Gratacap and 

 Mr. Bryant Walker in the identification of some of the species. 



TINIONIDAE FROM AN INDIAN GARBAGE HEAP. 



BT DR. A. E. ORTMANN, CARNEGIE MUSEUM, PITTSBURGH, PA. 



On the western banks of the Monongahela River in southwestern 

 Pennsylvania, upon the flood plain at the Point Marion Ferry, in 

 Greene Co., opposite the point where the Monongahela and Cheat 

 rivers unite, the writer found on July 9, 1908, a heap of Vnionida 

 shells, buried about one to two feet in the soil on the side of a road. 

 The soil consists of the characteristic river-silt of this region. Since 

 Indian " relics " have frequently been found at this place, in fact, 

 since it is known as the site of an old Indian settlement, it seems 

 beyond question that this pile (about 2 feet high) represents an old 

 Indian garbage heap of shells which had been used for food. 



When first found, the shells were rather brittle and soft, and many 

 of them crumbled to pieces. But enough were secured, which re- 

 mained whole, and subsequently they have hardened. They look 

 like fossil shells in so far as in most of them the epidermis, and with 

 it the color, is gone (only in a few Quadrulas fragments of the epi- 

 dermis remain). In species, where the nacre originally is colored 

 ( Unio gibhosus and crassidens), the color has entirely faded away, or 

 only very slight traces of it are discernible. 



It is hard to say how long ago this pile was formed : it may be 

 less than a hundred years old. But this does not matter. The 

 interesting fact about it is that this shell heap has turnished a small 

 collection of Unionida, which contrihutes considerably to our knowl- 

 edge of the Uniontda-faun-d of tlie Monongahela River drainage. 



At the present time, on account of the pollution of the water, this 

 fauna has completely disappeared in the Monongahela proper : there 



