170 C. LAPWORTH ON GRAPTOLITES 
The most characteristic forms from the zone are :— 
Didymograptus sagittarius, (Hall non Hisinger.) 
Cœnograptus gracilis, Hall. 
Dicellograptus sextans, Hall. 
Lasiograptus mucronatus, Hall. 
Climacograptus antiquus, Lapworth. 
Diplograptus Whitfieldi, Hall. 
So far as known, these are peculiar to this zone, and the presence of a single one 
of these species is sufficient to settle the age of the rock in Great Britain, and in all 
likelihood in America. With these peculiar forms, however, are associated others, which 
have amuch longer vertical range, and unite this zone to the one which follows it in 
order of time. These species of long range are :— 
Dicranograptus ramosus, Hall. 
Glossograptus ciliatus, Emmons. 
Diplograptus putillus, Hall. 
Climacograptus Scharenbergi, Lapworth. 
They all pass up into the British zone next above the Coenograptus zone, together 
with the following species, which range up through at least three complete zones :— 
Diplograptus foliaceus, Murchison. 
Climacograptus bicornis, Hall. 
This special Marsouin zone, now under consideration, has long been recognized by 
geologists upon the continent of America. Its fossils were described many years ago by 
Professor J. Hall, in his “ Paleeontology of New York,” from the dark shales of Norman’s 
Kill, near Albany, in the valley of the Hudson River. Hall also referred to the detection 
of the Norman’s Kill fossils on Marsouin River by Sir William Logan and the Canadian 
Survey; but the discovery of the existence of rocks containing the Norman’s Kill fossils 
as far down as Griffin Cove and between the Marsouin and Quebec, as demonstrated by 
the present collection, is wholly due to those officers of the Geological Survey of Canada, 
who have studied the district since the retirement of Sir W. Logan. There can be no 
question of the general identity of this Griffin Cove rock and the Marsouin Cœnograptus 
zone with that of the Norman’s Kill of the Hudson River valley. The New York 
geologists have always adhered to the opinion that the Norman’s Kill beds are of the age 
of the Hudson River group (Lorraine) or of that of the Utica Slate. The best advocacy for 
the last named view will be found in a letter from Mr. R. P. Whitfield, addressed to Dr. 
White, and published in the Report of the Geological Survey of the 100th meridian (Vol. 
IV. p. 101) ; in which it is asserted that G. serratulus, Hall, D. pristis, C. bicornis and D. ramosus 
occur in the Utica Slate of the valley of the Mohawk. I have myself referred to the 
Norman’s Kill beds in my paper on the Moffat Series (Quaterly Journal of the Geological 
Society, 1878, p. 335) as probably rising out unconformably from below the Trenton Lime- 
stone, and forming the highest portion of the convoluted rocks of the so-called Quebec 
Group,—a view also held by Dr. Sterry Hunt. At a later date (see “Distribution of 
Rhabdophora,” 1880, pp. 30, 28, etc.), while I refused to allow their equivalency with the 
Lorraine Shale (Hudson River Group), I reluctantly admitted that it was very probable 
