Lawson.1 



Post-Pliocene Diastrophism. 



141 



deeper. They were thus developed when the rear of the terrace 

 was at base level, and since the uplift they have not had time to 

 lower their trench into the new terrace. The drainage from these 

 ravines runs out over the surface of the terrace, and has in each 

 case inaugurated a gorge which is heading back from the present 

 sea-cliff toward the source of the stream. This state of affairs char- 

 acterizes only the small water courses. The larger streams, which 

 come from the mountains, and which are antecedent to the uplift, 

 have effectually trenched the terrace. 



The second terrace is also a broad one, and cuts into the same 

 shale. Its maximum width is, however, less than half a mile, and 

 generally the terrace does not exceed a quarter of a mile across. 

 The bevelment of the slightly inclined strata at the surface of the 

 terrace is here again well displayed in many sections. The higher 

 terraces are cut partly in the shale and partly in the complex of 

 metamorphic rocks and granite which rises from beneath it. The 

 granite is generally more or less decomposed. The metamorphic 

 rocks are, however, hard and fresh. The limestone has the char- 

 acter of a coarse marble. In addition to the terraces which are so 

 apparent from shipboard off the coast, there are several others of 

 higher elevation which are more or less obscured by the shrubbery 

 and trees which flourish on the upper slopes. These are all strewn 

 with shore drift, usually in the form of small, water-worn pebbles, 

 and occasionally, on the highest terraces, these pebbles are aggre- 

 gated and cemented together to form a conglomerate of local extent. 

 An effort was made to ascertain the altitude of the various terraces 

 examined by means of a mercurial barometer. The following fig- 

 ures were thus obtained, the point of observation being in each case 

 the rear of the terrace where it abuts upon its sea-cliff. The only 

 exception to this is in the case of the highest terrace, where on the 

 line of our examination a stream has cut back so as to have carried 

 away the rear portion of the terrace. The figures for this terrace 

 may, therefore, be a little lower than the true altitude of the strand 

 line. The altitudes are 1,201, 1,133, 1,025, 969, 871, 712, 374, 205, 

 and 96 feet above tide. 



Above the 1, 201-foot terrace there are no traces of any kind of 

 shore action, and the slopes rise ruggedly for several hundred feet 



