140 



THE AMEHICAN MONTHLY 



[May, 



Diatoms of the Connecticut Shore. — Y. 



By Wm. a. terry, 



BRISTOL, CONN. 



M. Tempere of Paris writes that in cleaning the samples of 

 earth from the Leete's Island deposit he failed to find many varie- 

 ties which were shown in the slides previously sent to him. The 

 earth was thrown out in digging for foundations for a railroad 

 bridge across Leete's creek. After digging some seven feet, piles 

 were driven through the deposit 20 or more feet and the abutment 

 was built up on the piles. The earth was carted away in wheel- 

 barrows and dumped. The strata became hopelessly mixed. 

 Besides, the same stratum varies greatly in richness within a few 

 feet of horizontal distance, as will be readily understood when the 

 method of deposit is studied. The rise of the tide along the 

 Connecticut shore averages about six feet, causing powerful cur- 

 rents in the bays and inlets, which deposit the diatoms in eddies 

 and basins. As frequent changes occur, the diatoms are very 

 unequally distributed. In describing the diatoms of Morris cove, 

 in an article published in this Journal in Dec'r, iSSS, I showed 

 how certain varieties grow in narrow belts or zones, limited by 

 the depth of water. These belts were only a few feet in width 

 but some miles in length, and occurred one after the other from 

 the shallow margin to about 15 feet depth of water at low tide. 

 Subsequent investigation has shown that this arrangement is per- 

 manent, and I can always rely upon finding certain varieties in 

 active life along a line at a particular depth and distance from the 

 beach. This shows how useless it is for an explorer to make a 

 dip here and a sounding there, and go away with the idea that he 

 understands the diatoms of any locality. Persistent and syste- 

 matic search is needed in order to arrive at anything like the 

 truth. The following list is from the 15th fascicule of the collec- 

 tion of J. Tempere and H. Peragallo. 



No. 492. Leete's Island, U. S. A., No. i. Lourd. 



Actinocjclus ehrenbergii Ralfs. 

 Actinoptychus undulatus E. 

 Amphiprora elegansSm. 

 pulchra Bail. 

 Biddulphia pulchella Gray. 



rhombus Sm. 

 Coscinodiscus excentricus E. 

 oculus iridis E. 

 radiatus E. 

 Lithodesmium undulatum E. 

 Melosira sulcata K. 

 Navicula formosa Greg, et var. 

 fusca Greg. 

 lyra E. var. 

 granulata Breb. 

 marina Ralfs. 

 Nitzschia circumsuta Bail. 



Nitzschia scalaris Sm. 



sigma Sm. 

 Pleurosigma affine Grun. 



balticum Sm. var. 

 strigosum Sm. 

 wansbeckii Donk. 

 Pyxilla dubia Grun. 

 Raphoneis gemmifera E. 

 Rhabdonema adrialicum K. 

 Scoliopleura tumida Breb. 

 Stauroneis salina Sm. 

 Surirella fastuosa E. var. 

 febigerii Lewis, 

 striatula Turpi n. 

 Terpsinoe musica E. 

 Triceratium antediluvianum E. 

 favus E. 



