262 
PALEONTOLOGICAL GEOLOGY 
represents, becomes a calculation in which only the Gods may 
indulge. 
When, not so very long ago, a dredge brought up from the bot¬ 
tom muds of the Chesapeake Bay a company of Lingulas, with 
their fragile, papery shells, indistinguishable from forms accurring 
in the old Cambric shales of the mountains in sight of the shore, 
it was evident that through all this long age between they had 
found shallow bay waters so congenial that they had come down 
these millions upon millions of years without appreciable modifica- 
' tion. Yet these lowly molusks had met the continent in its youth; 
they had watched it repeatedly wax and wane; they had wit- 
necessed for twenty-five successive times the Rocky Cordillera 
raised as majestically above the ocean’s waves as it stands today 
above the Colorado plain, and as often completely swept away 
and sunk beneath the waters of epicontinental seas. 
Overwhelmed by the effort to grasp the span of Lingula’s im¬ 
measurable antiquity, the late Dr. W. K. Brooks, once viewing 
the Chesapeake panorama with the eyes of an embryologist, fan¬ 
cied that were he standing on the shores of the Cambric ocean 
he could discern no clearer the ancestral path of this venerable 
shell-fish, than he could today through contemplation of its em- 
bryologic development. Although the pre-Cambrian history of 
Lingula may be of very great duration, it may not be in realitv 
so interminably long as embryology suggests, because we know 
that profounder changes often take place in organisms in single 
short epochs than in the millions of years that lie between. 
Nevertheless Lingula is the oldest, least-changed thing on Earth 
today, except the waters in which it swims. Kh^yES 
Balanocrinus in America. In view of the circumstances that 
no representative of the crinoidal genus Balanocrinus has ever 
been reported from American rocks the recent discovery of this 
type from the Late Cretacic beds of the San Felipe and Mendez 
formations of the State of Tamaulipas, Mexico, has special in¬ 
terest. 
The fossils were collected by Dr. L. W. Stephenson, and con¬ 
sist entirely of stem fragments, the other parts being entirely un¬ 
known. The genus ranges from Jurassic horizons to those of the 
Late Cretacic age. The species is designated Balanocrinus mexi- 
