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TRANSACTIONS OF SECTION D. 853 
8. Report of the Committee appointed to arrange for the Occupation of a 
Table at the Marine Biological Luboratory, Plymouwth——See Reports, 
p- 444. 
9. Report of the Committee on the Invertebrate Fauna and Oryptogamic 
Flora of the Fresh Waters of the British Isles. 
FRIDAY, SEPTEMBER 6. 
The following Papers were read :— 
1. Discussion on the Teaching of Botany, opened by Professors MarsHaLt 
Warp, F. Otiver, and ¥. O. Bower. 
2. On the Cretaceous Mammals of North Aimerica. 
By Professor O. C. Marsh, 
Remains of mammals have long been known from the Triassic and Jurassic 
formations, both in the Old World and in the New, all indicating animals of small 
size and low organisation. None were known from the Cretaceous, but in the 
Tertiary above this class was dominant, and even at the base of the formation 
was represented by many and various forms, 
A comparison of the mammals from the Jurassic and Tertiary made it certain 
that intermediate forms must exist in the Cretaceous, and for many years special 
search has been made for them in various countries, but until recently without 
success. ‘The most promising field was evidently in the Rocky Mountain region, and 
here a systematic search had been made. A few fragmentary remains were found in 
1882, but not in place. The author has since secured from the Laramie formation 
more than a thousand specimens of mammalian remains, including jaws, teeth, and 
various portions of the skeleton, most of them in good preservation. They repre 
sent many new genera and species, and were all found in the typical Laramie, 
either in place, or in association with other fossils that determine their geological 
position beyond doubt.1 
The vertebrate fossils found with them are mainly remains of Dinosaurs, 
which are represented by several families. The most abundant specimens belong 
to the Ceratopside, and with these are others allied to Megalosaurus, Hadrosaurus,, 
and related forms. Crocodiles, turtles, and various fishes, mostly ganoids, are also 
represented in the same deposits, which have been named by the author the 
Ceratops beds. 
The mammalian remains themselves also, to some extent, indicate their horizon, 
and this is one of the interesting points connected with the discovery. Many of 
them belong to the group the author has called the Adlotheria, which contains the 
Triassic Triglyphus, Tritylodon, and Microlestes, the Jurassic Stereognathus, 
Plagiaulax, and Bolodon in Europe, and Adlodon and Ctenacodon in America, as 
well as some later forms. 
Most of the genera show close affinities with the Triassic and Jurassic types, 
and one genus cannot at present be distinguished from Dryolestes. Another genus 
appears more like an insectivore, with teeth of the same general form as Jupaia. 
Besides these, there are several genera of small marsupials, which, although quite 
distinct, seem to have near affinities with some American Tertiary forms, or others 
still existing, especially the Opossums. 
Carnivores, rodents, and ungulates appear to be entirely wanting in this 
unique fauna. A still more surprising fact is the absence of their probable an- 
cestors, unless, indeed, the insectivorous forms are entitled to this important position. 
1 American Journal of Science, vol. xxxviii. pp. 81-92, plates ii.y. 
and pp. 177-80, plates vii—vili. August 1889. 
