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THE CRETACEOUS RIM OF THE BLACK HILLS.
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I; i.e., No. 12 of section I corresponds to the upper 30 feet of No. 4, section II.

At Minnekahta Station, in an ornamental heap of various minerals and rocks from the Black Hills, there were a number of fragments of cycads and fossil wood. We were told that these came from a ridge two miles to the southeast of the station that rises above the Red Beds and shows at its base low buttes and a considerable thickness of Jurassic. This was not visited, but it was evident that the summit of this ridge was formed by the hard sandstone No. 1 of section I (No. 5 of section II), which is continuous to Evans Quarry. The position of the cycad and fossil forest bed here is doubtless the same as on the opposite side of the valley where it was studied.

The occurrence of two other specimens of cycadean trunks, though apparently belonging to a different species, in the same general horizon on the east side of the Black Hills, and of silicified wood in the northern districts, seems to indicate that the same relations obtain on all sides, and this will probably be found to be the case.

The fossil plants of the lower horizon were sent to Professor Fontaine for determination, and the following extracts from his report upon them will show that my interpretation of their significance at the time of their discovery was for all practical purposes correct.

"The best preserved fragments are scattered leaflets, and the summits of the ultimate pinnæ of ferns, which are the parts of those plants which have great value in fixing species. The following are the plants:

"1. The summits of ultimate pinnæ of a fern, which is decidedly like Asplenium Dicksonianum Heer, from the Kome beds of Greenland. It has also something of the character of the widely diffused Potomac plant, Thyrsopteris rarinervis, but is, I think, nearer Heer's plant.

"2. Some ends of the ultimate pinnæ of a small fern with the facies of a Gleichenia. This is nearest to Heer's Gleichenia Zippei, from the same Kome beds, but the pinnules are rather more acute

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