136 PROCEEDINGS OF THE ACADEMY OF [1^<90. 



535 to 554, Sandy clay — Moderately rich in diatoms. 



554 to 560, Clear gray sand — No diatoms. AVater bearing stratum. 



Kan 4. K^K Altei'nations of pure clays) ^r i r ^ 



obO to 575, ^ •' > More or less diatomaceous. 



and sandy clays. ) 



575 to 600, Sandy clays — Moderately diatomaceous. 

 600 to 620, Brown clay — Rich in diatoms. 

 620 to 632, Brown clay — Diatoms in greatest abundance. 

 632 to 658, Chocolate clay and comminuted shell. Poorly diatoma- 

 ceous. 



The forms from the richest portions at 400, 525 and 625 feet, 

 have been most carefully observed under the microscope and identi- 

 fied by C. Henry Kain and E. A. Schultze. 



They have determined 149 species which are distributed among 

 49 genera. This includes a number of new species, named, described 

 and figured by them in the Bulletin of the Torrey Botanical Club.^ 

 They are indicated in the following enumeration which includes all 

 so far listed. There will probably, however, be a few forms yet to add. 

 Forms marked rare, are of rare occurrence in the well and not 

 necessarily so elsewhere. 



AcTiNOCYCLUS Ehrenbergii, Ralfs. 



AcTiNOCYCLus suBTiLis, (Grev.) Ralfs. 



AcTiNOCY'CLUs iNTERPUNCTATus, Bright. Rare. 



AcTiNOCYXLus Ralfsii, W. Sm. 



AcTiNoDiscus Atlanticus, n. sp., Kain & Schultze. 



ACTINOPTY'CHUS aREOLATUS, Ehr. 

 ACTINOPTYXHUS GrUNDLERI, A. S. 



AcTiNOPTY^CHUS SPLENDENS, (Ehr.) Grun. 



AcTiNOPTYCHUs ujsTDULATus, Ehr. var. Halion YX, Grun. Several 

 varieties. 



AcTiNOPTYCHus VULGARIS, Schumau, var. ViRGiNiCA, Grun. 

 Several varieties. 



Amphitetras minuta, Grev. Rare. 



Anaulus birostratus, Grun. Very rare. 



ASTEROLAMPRA Mary'landica, Ehr. 



AuLACODiscus Crux, Ehr. Two varieties. 



Aulacodiscus Petersii, Ehr. 



AuLACODiscus SoLLiTTiANus, Norman. 



AuLiscus Caballi, a. S. 



AuLiscus CffiLATUs, Bailey. 



iVol. xvi, pp. 71 to 76 and pp. 207 to 210; Plates LXXXIX., XCII., and 

 XCIII. 



