May 31, 1907] 



SCIENCE 



857 



classification and nomenclature for future 

 consideration; nor does he fail to indicate 

 what must be of the greatest interest to those 

 who are concerned in the solution of broad 

 biological problems, that a study of the seed 

 is certain to reveal much of the highest impor- 

 tance, and we are led to believe that on a 

 future occasion the author may take up this 

 part of the subject more in detail. 



The first cycadean trunks from America to 

 receive scientific mention were obtained from 

 the Potomac formation of Maryland and were 

 noticed by Philip Tyson in 1860 ; but for more 

 than a quarter of a century they remained 

 practically unnoticed until, in 1889, some of 

 the original Tyson specimens which had come 

 into possession of the Maryland Academy of 

 Natural Science were described and illustrated 

 in accordance with their macroscopic char- 

 acters by Fontaine. 



A further collection of Maryland cycads 

 was made in 1893 by Mr. Arthur Bibbins, and 

 this valuable material is now in the museum 

 of the Woman's College, Baltimore. Most of 

 it was gathered from various country people 

 between Baltimore and Washington, represent- 

 ing in all some sixty specimens which had 

 'been unsuspectedly sequestered from time to 

 time during the preceding hundred years.' 

 Much loss to science resulted during that 

 period, owing to the fact that, being regarded 

 with idle curiosity or with more or less super- 

 stitious interest, the specimens had been care- 

 lessly treated, while many of those which were 

 too large to handle with ease were broken up 

 and many valuable parts were lost. Charac- 

 teristic methods of branching were thereby 

 wholly destroyed. As later determined by 

 Professor Ward, this collection was found to 

 embrace seven species of Oycadeoidea. 



At various times trunks of cycads have been 

 obtained from other widely separated localities, 

 such as the Trias of Prince Edward Island, 

 the Dakota formation of southern Kansas, 

 from one or two localities in Colorado and 

 from California, but the richest deposit of 

 these remains is to be found in the Mesozoic 

 rim of the Black Hills of South Dakota and 

 Wyoming. 



Scientific attention was not directed to this 

 locality until 1893, although on several pre- 

 vious occasions miners proceeding to Dead- 

 wood had observed them at Black Hawk and 

 Minnekahta; but at that time six silicified 

 trunks were received at the United States 

 National Museum, and five years later they 

 were described by Ward, who found them to 

 include four species- of Oycadeoidea. This 

 collection, together with another lot of twenty 

 trunks obtained by Professor T. H. MacBride 

 later in the same summer, served to arouse 

 great interest and to awaken the special en- 

 thusiasm of Professor 0. C. Marsh, of Tale 

 University, whose efforts to secure a represen- 

 tative collection resulted in placing more than 

 seven hundred trunks, many of them of large 

 size and fine preservation, in the Tale Mu- 

 seum. This truly magnificent series furnishes 

 the greater part of the material upon which 

 the present monograph is based. 



In the Freezeout Hills of Carbon County, 

 Wyoming, there is another cycad locality 

 which ranks as third in importance on this 

 continent. The discovery of this locality is 

 due to Professor Marsh, who obtained a very 

 large collection of specimens representing ex- 

 clusively the genus Oycadella. 



An examination of the American distribu- 

 tion of the cycads shows them to be repre- 

 sented in the following geological horizons: 



1. Trias of Prince Edward 



Island Oycadeoidea, 1 



2. Trias of York, Pa Cyoadeomyelon, 1 



3. Upper Trias of North Caro- 



lina Cycadeoidea, 1 



4. Jurassic of Colorado Cycadeoidea, 1 



5. Upper Jurassic, Wealden or 



Cretaceous of the Black 

 Hills of South Dakota 

 and Wyoming Oycadeoidea, 27 



6. Upper Jurassic of Central 



Wyoming and Black Hills, 

 and from Freezeout Hills, 

 Wyoming Oycadella, 21 



7. Potomac Formation of Mary- 



land Oycadeoidea, 7 



8. Lower Chico of Colusa 



County, Cal 1 



