THE NAUTILUS. 35 



that they have been killed out by the sawdust from the mills above. 

 On this river are the celebrated Damariscotta shell heaps composed 

 almost wholly of oyster shells, and varying in depth from a few feet 

 to more than sixty feet. Some of the oyster shells from these heaps 

 are more than a foot in length. 



At Old Orchard arid Higgin's Beaches the shells are very differ- 

 ent from those found on Peak's Island or in the Damariscotta 

 River. Here are found, on the sand, between high and low water 

 mark, Cyprina islandica, Tellina tenera, Ensis Americanus, Siliqua 

 costata, Mactra solidissima, Nassa triviltata(very fine specimens), Ly- 

 onsia hyalina, Scala greenlandica, Bela harpularia, Periploma ( Coeh- 

 lodesma) leanum, Modiolamodiolus, Mya arenaria, etc. Clinging to 

 the seaweeds thrown up by the surf, I found Tmchydermon ruber, 

 Anomia glabra, Anomia aculeate. Also found at Higgin's Beach, a 

 very fine Petrieola pholadiformis. 



GENERAL NOTES. 



THE collection of Dr. P. P. Carpenter, the well-known authority 

 on West Coast shells, has been purchased by the Field Columbian 

 Museum of Chicago. 



DISPERSAL OF SHELLS. In his book on the " Dispersal of 

 Shells," Mr. Kew mentions floating pumice-stone as a possible 

 means of dispersal as pointed out by Mr. Bates and Sir C. Lyell. 

 As a slight contribution to dispersal, or possible dispersal, by this 

 means, I may say that on November 18th last I picked up a piece 

 of poroua blast-furnace slag, about <Sx6x2 inches, that contained 17 

 individuals of Zonites nitidus Miill., radiatulus Alder and arboreus 

 Say, all hibernating. This slag was lying among drift on the bank 

 of the Ohio River and the nearest point from which it could have 

 come is at least 10 miles above the point where it was found. As 

 the slag is very light and floats hir/h in the water, it would prob- 

 ably travel a considerable distance before the shells were all drowned 

 and thus a colony of Z. nitidus, a northern shell, might he started a 

 considerable distance down the Ohio. GEO. H. CLAPP, Pittsburgh, 

 Pa. 



