492 EMMONS AND MERRILL — SKETCH OF LOWER CALIFORNIA. 



two would be afforded by the various en echelon ranges known as the San 

 Jacinto mountains, San Bernardino mountains, etcetera, lying to the 

 northward, while the southern extension of the Coast range proper, cut 

 off by the reentering angle of the coast between Santa Barbara and Los 

 Angeles, would be represented by the chain of islands, Santa Catalina, 

 San Clemente, etcetera, generally known as the Channel islands, lying 

 off the coast between Los Angeles and San Diego. 



To the south of San Diego the mountains come down to the sea and 

 the mesa disappears, being only represented by an occasional patch of 

 later beds which have escaped erosion, as at Sausal and Todos Santos, 

 60 miles south of the boundary. At Cape Colnett, in latitude 31°, a strip 

 of mesa again forms the immediate coast and widens southward toward 

 San Quentin, in latitude 30° 30', which is assumed to be about the limit 

 of the northern or mountainous province. From San Quentin south- 

 ward, as far as examined by the writers, the mesa structure is character- 

 istic of the Pacific coast, the tablelands rising to a height of one to two 

 thousand feet at comparatively short distances from the sea and pre- 

 senting bold bluffs of soft horizontally stratified beds, often capped by 

 lava flows, which are evidently wearing awa}^ rapidly under the erosive 

 action of the waves. 



Lindgren, as a result of his observations in the vicinity of Ensenada 

 de Todos Santos, divides the topographic features of the peninsular Sierra 

 into three sections : 



1.- The Coast range, or the first orographic block, rising gradually from the sea to 

 an elevation 3,000 feet in a distance of 20 to 30 miles. Surmounting this are sev- 

 eral minor ranges and sharp peaks attaining an elevation of 3,000 to 4,000 feet. 

 A rapid descent leads from the divide of the Coast range to — 



2. The Interior valleys, an interrupted series of depressions in the middle of the 

 chain at an elevation of 1,800 to 2,000 feet. 



3. The eastern range, or second orographic block, rising rapidly from the valleys 

 and continuing as an almost level plateau, with a gentle slope up to the peninsular 

 divide and an abrupt, almost precipitous, descent to the desert. The elevation of 

 this remarkable plateau is from 4,000 to 5,000 feet. 



This plateau region, which supports a considerable growth of pinp 

 forest, extends, according to the meager accounts obtainable, from the 

 boundary southward about to latitude 31°, reaching its culminating 

 point in the high mountain mass now known as San Pedro de Martis, 

 which is apparently the same as the snow-capped mountain called in 

 the Narragansett report " Calamahue " or Santa Catalina (Caterina) 

 mountain. 



The area examined by the present writers, which extends 15 to 30 

 minutes north and south of the 30th parallel of latitude, is separated by 



