46 THE AMKKICAN MONTHLY |lVl.iuaiy, 



twcntv Icct :«l>o\f the lH)(tom of the tlcposit. What the strata 

 Ih'Iow this contains I liavc not vi't lonnii out. bnt hope to do so 

 h dealt IT. 



On the north side ot" the ishunl ti.e niaish \\ iilens out into 

 what was once a hroail hay, and extends northward lor some 

 miles; under all this marsh lies the diatomaceous clay. Much 

 of this clav is by no means rich, hut all contains some diatoms, 

 not a sinjjie ounce that I have examined luit what would yield 

 (lintoms enough for many dozen of slides. Since my previous 

 article was written I have partially explored Leete's Island 

 creek. I find it, like Morris and Stony ciceks. rich in /'. 

 a til erica Num. In a ditch Howing into this creek I find P/curo- 

 sif^ntii tcrrvamiiii with \ai'/cii/(i iiiacu/ata, both in such 

 abundance that they may be easily separated from other lorms, 

 and form bv themselves a nearly pure «jatheiiny^; with them 

 appear also an abundance of A'a: •/(/// a />rri>iai;ini of a peculiar 

 type, and large specimens of \iizsc/iia sca/ar/s. 



This I consitler a choice find. I have never heard of any- 

 thing like it elsewhere, and I think all the Leete's island slides 

 specially interesting. I have lately examined the upper stratum 

 from difVerent points, and find it extraordinarily rich in Xavicu/a 

 didymiis and other types of ^V. coustricta . and also tl)c dillerent 

 type's of X. elliptica. 



West of the ilcpot a new track has been laid tiirougli the marsh, 

 anil in building bridges and culverts a considerable amount of 

 the deposit hasbeen thrown up : this contains the same Cosciiiodis- 

 cus. Actiiioptycliiis, Amphora. RJialnioncma. Navicula. Scolio- 

 plcura, Orl/iosira. Surirclla ftbc^crii^ with a larger amount 

 of Acthiocxclus crassus. Au/isc/is scn/ptus, Canipyloiiiscus 

 echciicis. etc. Of recent material I found, in one gathering 

 from a ditch near the culvert, Plcurosigma ballicum. /'. tcrry- 

 anum.P. ostrt'gilis. P. amcricanum., P. decorum. P.clougatuin., 

 P. {Colletoncma) cximiuw. /*. brclussonii^ P. fasciola., P. 

 paradoxum. P. atigulatum. P. ajffiuc., and many others, with 

 sigmoid Xitzschia. large and small, in such annoying abundance 

 that it was impossii)le to separate the Plcurosigma so as to make 

 a satisfactory slide. 



In mv description of the diatoms of New Haven harbor and 

 neighboring waters, published some years ago in this Journal, I 

 mentioned that Plcurosigma aiigulalum was universally dis- 

 tributed in these waters. In this statement I was misled by va- 

 rious experts to whom the slides were sent for determination ; I 

 now find that the species they called augulatum was P. ajjiuc, 

 which is found nearly everywhere on the Connecticut shore, /'. 

 atigulatum being comparatively rare in deeper waters, and appear- 

 ingonlv occasionally in the shallow water of ditches and tide-pools. 

 The large /'. baiticum var. maximc is found in nearly all the 

 shallow tide-pools near the open salt water ; with it frequently 

 appears /'. clongatum. and ^ometimes P. aiigulalum : the tide- 



