REVIEWS 183 



From an economic standpoint this district has not yet proved a dan- 

 gerous rival of its sister regions farther north in the Cceur d'Alene Moun- 

 tains. The valuable minerals are chiefly confined to the western slope of 

 the Clearwater Mountains. Gold, in fissure veins and gravels, is the most 

 important mineral. Some few prospects of copper, silver, and silver-lead 

 ores have been worked. Elk City is the chief center of the mining industry 

 of the region. 



Some fair coal of a lignitic character, and of probably Tertiary age, has 

 been discovered, but may -not prove profitable on account of the thinness of 

 the beds. This lignite is found in two rather remarkable associations. In 

 one case the lignite is interbedded with rhyolitic flows, and in the other in a 

 series of sediments intercalated in the Columbia River basaltic flows. 



It is evident that this region, because of its great extent and rugged 

 character could merely be skimmed over in a reconnaissance, and, doubt- 

 less, much of interest yet awaits the scientist and practical miner. 



W. D. S. 



"A New Marine Reptile from The Trias of California," University 

 0} California Publications, Vol. Ill, (1904), pp. 419-21. 



Among the recent discoveries in vertebrate paleontology, none is of 

 greater interest than that by Dr. Merriam of a new order of marine reptiles 

 to which he has given the name Thalattosauria, from the typical genus 

 Thalattosaurus Merriam, from the Upper Trias of California. This new 

 order presents many of the peculiar aquatic adaptations of other well- 

 known, marine saurians, though differing markedly in structure. The 

 skull is elongate; the vomers (prevomers) and pterygoids are covered with 

 flat, button-like teeth, primitive characters lost in all other marine reptiles, 

 save the pterygoid teeth of the mosasaurs ; the dorsal ribs are single-headed ; 

 and the bones of the limbs are short, though the pelvis is robust, indicating, 

 either incomplete aquatic adaptation, or a short non-propelling tail. The 

 order is related, the author thinks, more to the early rhynchocephaloid 

 reptiles than to the ichthyosaurs. Further information concerning these 

 strange reptiles will be awaited with interest. 



s. w. w. 



"Neue Zeuglodonten aus dem unteren Mitteleocen vom Mokattam 

 bei Cairo," Geologisch-Palaontologische Abhandlungen, Vol. 

 VI (1904), p. 199. 

 A startling suggestion as to the origin of the Zeuglodon "whales" is 



that given by Professor Fraas in a recent paper on the Zeuglodonts from 



