1895.] NATURAL SCIENCES OF PHILADELPHIA. 157 



This vast growth of vegetation implies several conditions of exist- 

 ence. The climate must have been moderately warm, very moist and 

 the whole surface of the land slowly subsiding. The whole territory 

 lay at a very small elevation above the sea and but a slight oscilla- 

 tion of the land was necessary to place the whole again within the 

 grasp of the sea. 



How many times these conditions were repeated we do not know. 

 That would depend upon the number of lignite beds, but as these 

 have not been correlated with each other, if indeed they ever can 

 be, over any more than small areas, even these cannot be taken 

 absolutely as a chronometer reliable enough to indicate the number 

 of oscillations that may have taken place. 



Towards the close of this stage there came a time, however, in 

 which the sea began to assert its right of domain and to again cover 

 the face of the country with sand and sandy clay. This time is 

 represented in the beautifully striped or banded beds of the Queen 

 City deposits. The time of lignite making had come to an end and 

 a new order of things commenced. These beds represent a period of 

 comparative quiescence, and from the uniform thickness of the lamina- 

 tion and alternate banding of red and white sands and clays, appear 

 to have been a beach formation. How far these beds covered the lig- 

 nites is not known; they are only found as remnants of what probably 

 was a very widely extended series of deposits. Their northern boundary 

 shows signs of extensive erosion and their southern margin has never 

 been seen. 



The relative time of deposition of these beds could not have been 

 very long as the greatest thickness found anywhere does not exceed 

 65 feet. They probably represent a period in which the land lay 

 very low and open to a long sweep of tidal waters. 



A slight change in the relative positions of land and sea again 

 brought deeper water along the Texan coast and heavy beds of sand 

 were heaped up and spread along the shore. A few of the marine 

 forms of life began to appear. Amoug them we find some such as 

 Veriericardia planicosta, Tiirritella sp., and which had survived 

 the changes from the basal beds up. This condition continued 

 until nearly 300 feet of sands and sandy clays had been deposited. 

 The faunal life increased somewhat during that time but did not, so 

 far as our evidence shows, reach the quantity of richness of the 

 latter half of this period. 



