GLOSSARY. 



823 



Benton — lower division of Colorado 

 formation ; Great Plains region. 



Berea grit — division of the Waverly 

 group. 



Bertie waterline — upper Siluric of west- 

 ern New York. 



Bethany Falls formation — upper Car- 

 bonic of Kansas. 



Bethany limestone — base of the Mis- 

 sourian or upper Coal Measures of 

 Iowa. 



Bi — a prefix meaning twice or doubly. 



Biconvex — with both valves convex, as 

 in most brachiopods and pelecypods. 



Bidentate — having two teeth. 



Bifid — split into two. 



Bifoliate — two-leaved. Those Bryozoa 

 are said to be bifoliate in which there 

 is a union of the basal epithecae of 

 two parts of a colony, producing a 

 mesotheca. 



Bifurcating — dividing into two, forking. 



Bighorn limestone — middle-upper Ordo- 

 vicic, Montana. 



Bilateral — pertaining to the two sides 

 of a body. 



Bingham quartzite — upper Carbonic of 

 Utah. 



Biramous — with two branches. 



Biserial — with double series or rows ; 

 for use in crinoids, see II., 490, and 

 Fig. 1806. 



Biserial pores — in echinoids, see 

 pores. 



Bivium — see trivium. 



Black Hand formation — division of the 

 Waverly group of Ohio. 



Black River limestone — middle Ordo- 

 vicic. New York, etc. 



Blanco — middle(?) Pliocenic of Texas. 



Bliss sandstone — Cambric, Rio Grande. 



Body chamber — the latest formed cham- 

 ber of a cephalopod shell, enclosing 

 the soft parts of the animal (see Fig. 

 1230, and II., 20). 

 Bonnterre limestone — middle Cambric, 



Ozark region. 

 Boone chert — lower Mississippic of Ar- 

 kansas. 



Boss — in echinoids, the base of a 



tubercle. 

 Boston group — upper Mississippic of 



Arkansas. 

 Bosworth formation — upper Cambric, 



Canadian Rockies. 

 Bourrelet — in some echinoids the in- 

 flated interambulacral plates divid- 

 ing the floscelle (see Fig. 1930, a, e). 



Bowden beds — Oligocenic of Jamaica. 



Bow River group — lower Cambric of 

 Canadian Rockies. 



Brachia — plural of brachium, an arm. 

 In brachiopods, those portions of the 

 lophophore which diverge arm-like 

 from the two sides of the mouth. 



Brachial — pertaining to the brachia or 



the arms of vertebrates, brachiopods 



and crinoids ; one of the arm plates 



of crinoids, usually distinguished 



as costals, distichals, palmars, etc. 



Brachial valve — in brachiopods, the 



valve to which the brachia were 



attached. This is the dorsal valve 



and usually the smaller (see L, 



170). 



Brachidia — plural of brachidium. In 

 brachiopods, the calcareous ribbons 

 or internal skeleton for the support 

 of the fleshy brachia (see I., 173, Fig. 

 220). 



Brahmanic — lower division of Triassic. 



Braintree beds — middle Cambric, east- 

 ern Massachusetts. 



BranchicB — gills. 



Branchial — pertaining to the gills. 



Branchlet — a little branch or twig. 



Bretonian — a term for the upper Cam- 

 bric (Grabau), as used by Matthew 

 includes some Ordovicic. 



Bridger beds — middle Eocenic of Wyo- 

 ming. 



Bryozoilm — the entire compound colony 

 of bryozoa. 



Buda limestone — upper Com.anchic of 

 Texas. 



Burlingame limestone — upper Carbonic 

 of Kansas. 



Burlington limestone — lowest division 



