OLDER POTOMAC OF VIRGINIA AND MARYLAND. 533 



Sequoia cycadopsis Fontaine. 



PI. CIX, Fig. 11. 



1889. Sequoia cycadopsis Font.: Potomac Flora (Monogr. U. S. Geol. Siirv., Vol. 

 XV), p. 24.3, pi. cxii, figs. 9, 9a, 10, 11, 11a; pi. cxiii, figs. 1, la, 2, 2a, 3. 



This is a well-marked species that is highly characteristic of the 

 Aquia Creek horizon. There was obtained from Rosiers Bluff a very- 

 good specimen that shows the terminal part of an ultimate twig with 

 a number of well-preserved leaflets. The rock matter containing it is 

 somewhat different from that showing most of the specimens of Rosiers 

 Bluff, as it is an ash-gray pure clay." 



FOSSIL PLANTS FROM KITEKDALE. 



[PI. LXXX, No. 129.] 



In the collections there are four clay casts of small cones credited 

 to the locality Riverdale. This locality is a cut on the electric rail- 

 road between Hyattsville and Riverdale and about midway between 

 these two places. The bed is referred to the Arundel formation. The 

 cones appear to belong to Athrotaxopsis expansa. This small amount 

 of material is of course not sufficient to determine positively the age 

 of the beds yielding them, but, so far as their evidence goes, it con- 

 firms the assumption that it is Rappahannock or Arundel. The speci- 

 mens were collected by Mr. Arthur Bibbins, three of them on July 1 

 and the remaining one on July 28, 1896. This last is much larger than 

 the others. It was obtained by Mr. Bibbins on an excursion in com- 

 pany with Professor Ward, to whom it was given, and it was deposited 

 by the latter in the National Museum. The others are the property 

 of the Maryland State Geological Survej^ and bear its number, 8248. 



« There is a shade of doubt as to whether this specinjen actually came from Eosiers Bluff. The locality 

 number, as often happens, had become detached and was lost before it was sent to Professor Fontaine. I am 

 sure that I collected it myself in the soft clay, and I had trimmed the sides in the field with a knife that I cany 

 for the purpose. I had also carefully worked out the impression with the proper tools. Finding it in the 

 collection made by Mr. White and myself on November 25, 1891, without a number, I wrote the number 

 plainly with a pencil on one of the smooth-cut surfaces, then dry and well adapted to be written upon. In 

 this form it went to Professor Fontaine, but the difference in the character of the matrix did not escape him, 

 and he made the above note on this fact. It is, indeed, wholly different from that of any other specimen from 

 the Rosiers Bluff locality, and there is no essential difference in the matrix of any of the other specimens from 

 this locality. I have carefully compared it with all the other collections described in this paper and it does 

 not exactly agree with any of them, but is much nearer to that from the 72d Milepost and the bank near 

 Brooke. As this species had previously been found only at the former of these last-named localities, it is 

 possible that the specimen is from there. The horizon, however, is the same. — L. F. W. 



