42 GYMNOSPERMS 



others combined, has prepared his own material for microscopic 

 study, developing excellent methods, and has made his own draw- 

 ings, photographs, and photomicrographs. Three large quarto vol- 

 umes, with scores of plates and numerous drawings in the text, to- 

 gether with a clear and interesting literary style, present the results 

 of a lifetime of productive research. And besides there are numerous 

 shorter papers. 



DISTRIBUTION 



At this time, any account of the geographic distribution of the 

 Bennettitales must be regarded as merely a beginning. Whenever 

 WiELAND makes a trip into a Mesozoic region, a new locality for fos- 

 sil cycads is added to the list. Wherever members of this group have 

 flourished, they are likely to be preserved, because their armored 

 trunks and tough leaves, with heavy cuticle, make sharp impressions 

 even when no internal structure is preserved. In many localities the 

 material is silicified. 



American forms were first brought to notice in i860. Various peo- 

 ple picked them up between Baltimore and Washington and kept 

 them as curiosities, calling them fossil bee hives, fossil wasps' nests, 

 etc. W'ard^"-''^^'''^^ first described them and 60 were taken to the Wom- 

 an's College in Baltimore but have been removed to the Museum of 

 Natural History in Washington. Specimens have also been found in 

 North Carolina, Pennsylvania, Kansas, Colorado, Texas, and Cali- 

 fornia; but the most extensive collections have been made in the 

 Upper Jurassic of Wyoming and the Black Hills of South Dakota. 

 To protect the richest part of the Black Hills region, Wieland took 

 up 360 acres as a claim, and then succeeded in having it made a 

 national preserve. More than 700 trunks from this locality are now 

 in the Yale Museum, where, with many specimens from other lo- 

 calities, they constitute the largest collection in the world. Wieland 

 has recently discovered a rich locality (not yet described) in Arizona. 



Prince Edward Island, in Canada, has silicified Triassic material. 



Wieland,^** in 1909, visited the Mixteca Alta, near Oaxaca, Mexi- 

 co, and discovered a region wonderfully rich in fossil cycads. The 

 result of this investigation, published (in Spanish) by the Mexican 

 government, is illustrated with 50 excellent plates made from photo- 

 graphs. The principal genera in this locality are Ptilophyllum, Plcro- 



