Apr., 1921] WIELAND — MONOCARPY IN THE CYCADEOIDS 
227 
formation of Maryland in the Arundel (?) occurs the characteristic Cycade- 
oidea marylandica in latitude 39°. And twelve hundred miles to the 
southwest this same form recurs in Wise County, Texas, latitude 33°.^ 
About the same time the Arundel cycadeoids formed this southeastern 
continental fringe, a second and highly xerophyllous group of very small 
trunks finds a certain extension from the Freeze Out Hills of Wyoming to 
the Black Hills, or from latitude 42° to 44°. 
As the greatest of all American occurrences, the cycadeoids of the 
succeeding Lakota girdle the Black Hills in latitude 43° to 45°, while two 
isolated finds, which may be nearly associated, extend this range on from 
Colorado to California on the 39th parallel, about 1,000 miles. 
Correspondent to this greater North American extension, there is in 
Europe a triangle of occurrence with an apex in the Apennines in latitude 
44°, and with a base of 1,000 miles from the Galician Carpathians and 
Cracow in latitude 50° to the Isle of Portland in latitude 51°. As in America, 
the north-south limits are only seven degrees apart. But high in the upper 
Cretaceous these limits are slightly extended. In the Upson Shales of 
Maverick County, Texas, occurs the isolated Cycadeoidea Uddeni in latitude 
29°, while in the Belly River formation of Alberta, of nearly the same age, 
an undescribed cycadeoid is found at the north limit, latitude 54°. Whether 
this represents actual late extension of habitat cannot be said. 
Finally, the petrified cycadeoids of India come about on the Tropic of 
Cancer. Whence, unless the exigencies of silicification be so great that most 
of the record of the heavy-stemmed cycadeoids must forever lie hidden 
behind the thick veil of the paleontologic past, restricted habitats are 
inferable, and those always with a large part of the year decidedly dry. 
That the cycadeoid alliance as a whole was of cosmopolitan distribution all 
through the Mesozoic should indicate the further capacity to live in the 
most varied climates, as already maintained. But that which it is espe- 
cially desired to point out is that the greater silicified series of early Creta- 
ceous time falls at a period of considerable continental emergence, in North 
America at least, and goes far to indicate long arid belts there covering the 
35th-45th parallels, in Europe the 45th-5ist. Elsewhere attention has 
been called to the fact that the record for Asia and Africa, likewise for 
South America and Australia, fails. 
^ The Texas cycadeoid here referred to is so Hke the original Maryland type that it 
would be regarded as varietal if from the same locality. It is an isolated and thus 
remarkable find of Dr. Emilio Bose with whom I was associated as a paleontologist of 
the Instituto Geologico of Mexico during the years 1908-10. With great consideration 
Dr. Bose apprised me of his "find" the day it was made, in July, 1915, and later sent 
me the specimen. It is from the basal Trinity Beds. These rest on the Pennsylvanian, 
and are generally regarded as not the very oldest Cretaceous in the broader sense, but 
about the age of the European Aptian. 
