285 



remarkable for the curious distortion which many of tlie individ- 

 uals appear to have undergone, wliether from the influx of salt 

 water, (a likely occurrence, considering the locality,) or from 

 other causes, it is difficult, if not impossible, now to determine. 

 Two species, the largest, seem to have been most affected ; these 

 are Pinnularia major, which is very much distorted, and Stauro- 

 neis phoenicenteron ; Himantidium gracile has also, in some cases, 

 been distorted, but not to the extent observable in the two larger 

 species. Under the head of Eunotia serra I have in the above 

 list included several forms having elevations (S. V.) varying in 

 number from four to seventeen, as I am of opinion that they all 

 constitute one species. 



The Brooldine deposit. Dr. Shurtleff writes me, occurs under 

 the following circumstances : He says, " I found this under a bed 

 of peat of from six to twenty feet in depth ; it was in the form of 

 a stratum of marl, with roots or remnants of roots permeating in 

 every direction. The locality is in Brookline, about one half a 

 mile from the nearest salt-water inlet, but in a meadow lying up 

 on the high ground, many feet above the highest tide-water." 

 The species detected in it are : 



I have put down a form as Surirella Umosa, (Bailey.) This 

 species is figured by Brightwell (Mic. Jour. 1859) as founded by 

 Bailey ; after a careful search, neither Mr. Stodder nor myself 

 can find any allusion to such a species among the papers of Bai- 

 ley. It however is a distinct species, and may well bear the 

 name given to it. The Pinnularia mesolepta in this deposit has 

 invariably, as far as I have seen, a " stauros " or blank space on 



