1
43
1893—1902. Nottil ["05 ll, l-‘Al'h .' ‘tlttll 5 “IF
a few specimen are found to hr quite identical in view at the virtual- stance that the two regions are situalod more than I»; degrees nl' latitude (or altout 2400 miles) apart.
As to the detailed stratigmpliit-al relation hetween the heads in the different localities. or even helwcun lhe lower and upper part at the series which are distinguished hy Sunni. I dare not nilcl' any opinion, 0f the four species that are in cunlniml with the |\'ersur-launa of Mary- land, one is res
‘ted to the lower and one to the upper part. whilst the other two are found in hath. of other common speoios the new [reper- (Mia and Stenoc/(L’sum deakm'mtsis val'. arctica also occurs in huth div
ions, the latter form but in few and small specimens in the lower one. A considerable amount ol time must naturally have elapsed helwecn the deposition ot' the lowest and highest layers at a marine series, 1000 teat thick, and we [ind also that most 01' the lorlns are restricted to one olthe divisions. hut it is not on the other hand evident tram the tannal aspect that the two divisions, geologically speakin”, lie-lung to very different times.
No near relation to European iaunas has been found, and apart from the quite cosmopolitan [arms Lept. rhombnirialis, Alrypa reticu- laris, Thecia swindm‘euunu and the Favositcs forbesi—variety the other species differ irqu European ones.
This would not he the place to discuss, on the basis of a small immn like the above, the Silurian or Devonian character at the Keyser fauna. The correspomting zones at New York and New Jersey have been generally regarded as Silurian, in the "Lower Devonian" of Mary- land the Keyser is considered as the basis at the Devonian. 'l'heauthor.~ of the stratigraphical portion at this very important monograph, (Immas Scnucnen’r, C. K, SCHWARTZ. T. POOLE Maryann, and It. B. Howe. strongly emphasize the fact that the fauna of the Keyser. whilst mntaining a numher of species at Helderherg al’linilies has also a marked Silurian aspect.
We may quote from the reportp. UK: “These l’lelderhel 'perivs enl-
ered the Maryland sea in Keyser time, mingling with the Silurian species which continued to eonsitute the larger part of tho, lannas. 'l‘he Keyser limestone is, therefore, rlearly transitional hetweeu the Silurian and Devonian. Accepting the principle that the age of a l'orination is that of its youngest fauna. the Keyser is here referred to tln> Lower De- vonian although the majority of the species in it are distinrtly Silurian".
That the faunas ol the Series B at Ellesmereland, when seen
(letachedly, must be regarded as showmg in general a Silurian and not
