Walks and talks in the geological field . and extraordinary shells, which we callRudistes^ carted together and burned for lime to Rudistes,whitewash log-cabins. From Texas, the great Cretaceous belt can be traced ^ ° Western northward to Kansas, Nebraska, Minnesota, Dakota, localities,and British America. It extends, indeed, along theeast flanks of the Rocky Mountains, apparently tothe Arctic Ocean. These are interesting facts. Theydemonstrate that there was a time when an oceanstretched from the Gulf of Mexico, through the mid-dle of our continent, to the Arctic. These Cretaceousstrata contai


Walks and talks in the geological field . and extraordinary shells, which we callRudistes^ carted together and burned for lime to Rudistes,whitewash log-cabins. From Texas, the great Cretaceous belt can be traced ^ ° Western northward to Kansas, Nebraska, Minnesota, Dakota, localities,and British America. It extends, indeed, along theeast flanks of the Rocky Mountains, apparently tothe Arctic Ocean. These are interesting facts. Theydemonstrate that there was a time when an oceanstretched from the Gulf of Mexico, through the mid-dle of our continent, to the Arctic. These Cretaceousstrata contain neither chalk nor rotten were not formed in a deep sea. There are vastformations of clay and shale, and at the bottom is athick sandstone, often conglomeritic, which can betraced from Kansas to the Wahsatch Mountains—but not in one continuous sheet. All these Cretaceousstrata being formed of fragments coarse or fine arecalled fragmentaL Evidently they were laid downin waters mostly shallow, and to a great extent near. Lesson from a Lump of Chalk, 213 the shore. The western Cretaceous beds containmany strata of coal; and this is other evidence ofwater so shallow as to become frequently dry fine coals of Wyoming and of the Cascade Moun-tains in Washington are Cretaceous. These strata are the burial places of gigantic rep- Reptiles,tiles—dwellers in the sea and dwellers on the of their forms were amazingly elongate. Someattained a length of fifty to one hundred feet. Imust give you the name of one of these—Ca-mar^^-o-sau^-rus. The bones were found by Cope in Col- Camaro-orado. He says : One of the vertebrae of the neckwas twenty inches long and twelve inches in trans-verse diameter. The shoulder-blade was 5J feet long,and the thigh-bone five. The total length of thereptile must have been 72 feet. Am-phi-cmV-i-as Amphi-had a thigh-bone six feet in length and a body overa hundred feet long. Marsh has discovered, also,enormous reptilian bone


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Keywords: ., bookcentury1800, bookdecade1890, booksubjectgeology, bookyear1898