14 GEOLOGY OF THE DENVEli BASIX. 



The Colorado Island corresponded in a general way with the present 

 form of the Colorado and Wet .Mountain ranges. Its northwestern exten- 

 sion was, however, greater, probably taking in the present area of the 

 North and Middle parks and reaching to the Park Range beyond them. 



On the southeast, on the other hand, it was divided up into a series of 

 peninsulas or islands, by bays or straits extending into it in a northwesterly 

 direction from the ocean. The most important of these bays was that 

 between Canyon City and Pikes Peak, forming part of the South Park 

 depression, which max have entirely cut off the connections between the 

 Wei Mountains and die main island. A second important bay was that 

 which stretched up the present depression of the Ite Pass and Manitou 

 Park: and it', as is quite possible, the waters of the latter connected with 

 the Smith Park depression, the present Pikes Peak massive would also 

 have formed an island. There is some probability also that the present 

 promontory known as the Rampart Range, lying between Manitou Park 

 ami the plains, was more or less submerged beneath the Cambro-Silurian 

 seas and received sediments perhaps as late as the early Carboniferous, 

 having keen arched up into its present form during the later orographic 

 movements to which the region has keen subjected. Another prominent 

 ka\ was that now occupied by Huerfano Park, at the southern end of the 

 Wet Mountains, which it now separates from the Sangre de Cristo Range. 

 Conditions have keen so modified by later movements that in our present 

 state of knowledge it is impossible to determine definitely whether the Wet 

 Mountain Island was connected at that time with the Sangre de Cristo and 

 Sawatch islands or not. 



A similar uncertainty exists with regard to the northern portion of the 

 eastern shores of the Colorado Island, but judging from the present form of 

 the Mesozoic deposits it is probable that there were smaller bays, extending 

 to no great distance inland, which served to give an indented form to the 



shore-line. 



A.S shown hv the character of the sediments deposited there, on the 

 western shores of tin- island conditions differed somewhat from those mi 

 the eastern shore. The depression of Smith Park had certainly a connec- 

 tion with the ocean westward between the northern end of the Sawatch 



