819 



the fish spawned in the latter part of April and early May, 

 while here the spawning season was in December. 



Mr. Putnam said that his study of the Cods had led him to 

 consider that those found at the Banks and nortl*ward belonged 

 to the European species, while the American Cod was the 

 only one found in the waters of Massachusetts. 



Mr. C. Stodder exhibited a specimen of Diatomaceous earth, 

 Avith a slide of the same under the microscope. The speci- 

 men was from the land of Mr. D. Faxon, in Randolph, Mass., 

 found under the following conditions: — 



The surface of the country is gently undulating. There is slight de- 

 pression, with a level tract in the centre, nearly circular, of about one 

 hundred feet diameter, apparently like any ordinary New England 

 naeadow, flooded with water; but, on walking on to it, it is found, 

 unlike flooded meadow lands, to be not soft and miry, but nearly as 

 firm and hard as the surrounding dry land. The surface is covered 

 with grasses and turf two to three inches thick. Immediately below 

 that is found the material exhibited, which has in one spot been exca- 

 vated to the depth often feet without finding the bottom of it. It con- 

 tains vegetable matter, a few fibres, to the amount of five or ten per 

 cent. ; the remainder is entirely organic, nearly all whole or broken 

 frustules of Diatoms, with some spicules of sponges. Not one particle 

 of sand or other inorganic matter has heen discovered after the strict- 

 est search with the microscope. 



The Diatoms as yet have presented no species of particular interest. 

 The genus Himantidium is most abundant ; next, Linularia and Stau- 

 roneis. No attempt has been made to make any list of species found, 

 as all are common in thousands of sub-peat deposits in New England. 

 It would be a matter of interest to know If the species are the same at 

 different depths from the surface ; but no opportunity has yet been af- 

 forded for that, nor is it known from what depth the specimen ex- 

 amined was taken. 



Under what conditions could this enormous accumulation of Dia- 

 toms have been deposited ? An examination of land in the immediate 

 vicinity, has given the clew to a probable explanation. As already 

 stated, the locality is a slight depression from the general surface around. 

 There is a very small stream of water running into and through it. The 

 outlet is through a ridge of drift gravel, and has been artificially deep- 

 ened some five feet since the settlement of the country. Before this 

 lowering of the outlet, the place must have been a pond, with some 

 four to five feet of water above the present surface. The small stream 



