SOUTHERN CALIFORNIA ACADEMY OF SCIENCES. 77 



4. San Pcdran Epoch, deposition with surface below normal. 



5. Not named Epoch, of erosion prior to glacial epoch. This is assumed on 

 the author's premise that the San Pedran epoch is properly correlated with the 

 lowan epoch of eastern geologists. 



There is doubt of the propriety of the foregoing assumption, which Mr. 

 Hershey clearly admits. 



The Modern Epoch is represented by the flood-plains of our present rivers, and 

 it is regarded as an epoch Of deposition, with land level below normal. 



The marine Pleistocene, well exposed in Los Angeles, on Boyle Heights, is 

 referred to the Red Blviff epoch by Hershey; his Los Angelan epoch is here 

 represented by the silted-up valley of the ancient river, well shown near the 

 County Hospital and in the low terrace running partly through the city east of 

 Main Street; the Modern epoch allvivium, forming the flood plain of the present 

 Los Angeles River, is the next Ouarternary representative know to exist in San 

 Pedro hill, near the coast, overlying deposits of the earlier epochs. The marine 

 formations at the base of the hill are tentatively referred to the Red Bluff epoch. 



The late volcanic eruptions on Martinique and St. Vincent have proved a 

 "nine days' wonder" for the newspaper writers, but the ' scientific import has 

 been but barely touched as yet. Aside from the dynamic geological features, which 

 we may have occasion to discuss hereafter, there will undoubtedly be many very 

 startling revelations in physiography, terrestrial physics, chemical geology and other 

 branches of enquiry. We may look for the tinted atmosphereic effects hereabouts 

 within a few weeks. In a former instance of the kind, trained observers were 

 enabled to deduce new and unexpected movements of serial currnts actually follow- 

 ing them by the dust tracks several times around the earth. Chimical stvidies of 

 the ash accompanying the recent West Indian outbreaks show that the quality of 

 material is unlike that thrown out half a century earlier, and some interesting con- 

 clusions have already been drawn concerning the gaseous products of eruption, 

 which are supposed to have been the immediate cause of the annihilation of the 

 inhabitants. 



In some respects, in minute degree, our local coast and insular geology is akin- 

 to that of the West Indies, but we cannot predict the future history with certainty 

 from our limited understanding of tlie sub-structure. The theory of isostasy has, 

 at first glance, received unwelcome support from the catastrophe of Martinique, 

 but it is too early to generalize on that subject. From the investigations already 

 undertaken by members of the U. S. Geological Survey much valuable knowledge 

 may be anticipated. Dr. Angelo Heilprin and Dr. Robert T. Hill have gone to 

 study the district for that organization. 



The U. S. Geological Survey has just issued Sheets i and 2, (of a series of 

 three maps of Southern California), including Orange County, the major portion 

 of Los Angeles County and parts of Riverside and San Bernardino counties. The 

 scale is approximately four miles to the inch, size 21 in. x 33 in.( Price 10 cents 

 each; to be had on application to the Survey at Washington, D. C. 



As this Bulletin goes to press, we receive word that Dr. Robt. T. Hill, Pro- 

 fessor Israel C. Russell and C. E- Borchgrevink went together, on the Dixie relief 

 fessor Israel C. Russell and C. F. Borchgrevink went together, on the Dixie 

 ciety, of W'ashington, D. C. The selection has been peculiarly fortunate and we 

 shall soon have authentic information from these gentlemen, all of whom are 

 acknowledged authorities in this line of study. Dr. Hill has predicted the erup- 

 tions for a long time past. 



