Title: The Canadian field-naturalist
Identifier: canadianfieldnat1932otta (find matches)
Year: 1932 (1930s)
Authors: Ottawa Field-Naturalists' Club
Subjects:
Publisher: Ottawa, Ottawa Field-Naturalists' Club
Contributing Library: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library
Digitizing Sponsor: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library

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204 The Canadian Field-Naturalist (Vol. XLVI imprint of his feet, the sun dried the surface, so as to make a cleavage plane between this and the next layer of mud which was deposited. Or if the imprints were made under water the settle- ment of a slimy film or the deposit of a different type of sediment would make a cleavage plane so that the mud which filled the track would separate from the imprint. No doubt thousands of other tracks were made and filled but as there
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was no cleavage plane their presence can not be detected. Eight species of dinosaur footprints, ranging from less than 6 to 25 inches in length, were col- lected. The largest of these has been cast in concrete and mounted on a low base, in the grounds of the National Museum at Ottawa. This is a reproduction of a track described by the writer as Amblydactylus gethingi'^ signify- ing blunt-toed. The dinosaur which made this track is not known from the fossilized skeleton but the short, bluntly-pointed toes would suggest a herbivorous type similar to the European Iguanodon. The imprint (Fig. 1) is 25 inches long, 23% inches in greatest breadth and has an extreme depth of more than 4 inches. The sole of the foot was more deeply impressed than the toes. Behind the impression of the "heel" the rock slopes up- ward and backward. This probably represents the impression of the posterior edge of the meta- tarsals which were not quite perpendicular above the phalanges as the animal walked. At almost any time of day, during the warm weather last summer, birds could be seen en- joying a dip in this unique bath-tub. Those most often noticed were house sparrows, robins, bronzed grackles and catbirds. Though there was a colony of purple martins nesting near-by they were never observed in the bird bath. Dinosaur Footprint Bird Bath 'Sternberg, C. M., Ann. Rept. 1930, Nat. Mus. Can., pp 72-73, 1932. OBSERVATIONS ON THE OCCURRENCE OF OTTER IN THE RIDING MOUNTAIN NATIONAL PARK, MANITOBA, IN RELATION TO BEAVER LIFE By H. U. GREEN RIOR to a few days before Christmas, 1930, otter were thought to be extinct in the Riding Mountain, Manitoba (now the Riding Mountain National Park), as neither otter nor otter signs had been seen for many years. I was then informed by an old trap- per, now employed by the Park authorities in a less destructive capacity, that he had observed otter tracks in the snow near Lake Audy, close by Jackfish Creek. This small stream was then open in places, but froze up throughout its entire length early in January, 1931. I made notes of his observations. On February 3rd, 1931, when on patrol in the Park, I visited a beaver pond situated in the valley of the Vermilion River, one mile west of Mile 32 Cabin, Strathclair Road, known as Site No. 2. The Vermihon River at this point is a very small stream usually drying up in the fall of the year. The pond in question, however, is spring fed and brim full at all seasons. The deep- est part of the retaining dam is the filling in the river bed some 10 feet wide and 9 feet deep. The surplus water finds its main outlet over the crest of the dam immediately above the river channel. The area flooded fills the entire valley and is approximately 4 acres in extent. Six beavers in- habited the pond; a male and female with their four "kittens" born during the latter part of May, 1930.

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