1867.] COLLINGWOOD ISLANDS NORTH OF FORMOSA. 97 



I will also include in this notice a few words concerning the 

 Pescadores or Ponghou archipelago, situated between Formosa and 

 China, and between the parallels of 23° and 24° N. This cluster 

 consists of twenty-one inhabited islands, besides several uninhabited 

 rocks ; and the portion of the group which I had an opportunity of 

 seeing included Eound Island, Three Island, Table and Tablet 

 Islands, Pisher Island and Ponghou (the two largest of the group), 

 and Observation Island. All these are of volcanic origin and formed 

 of basalt. The characteristic features of basaltic formation were 

 best observed in Table and Tablet Islands, the general aspect of 

 which was striking and rather formal. Both these islands have 

 evidently derived their names from their flat and truncated appear- 

 ance. Table Island is a long and narrow ledge, two miles in length, 

 and presenting a dead-level surface, elevated 200 feet above the 

 sea, this flat table being supported upon a row of short basaltic 

 columns. Tablet Island is very similar in character also; and 

 in both of these islands the ground slopes outwards from the 

 bases of the columns, forming a talus of debris arising from their 

 disintegration from above, as is the case at the Giant's Causeway. 

 As we skirted the south shore of the large island of Ponghou, I 

 could also perceive basaltic columns in many places, often with a 

 sandy beach at their base ; and on approaching Pong Point, the 

 south-west promontory, I observed the columns to be broken off 

 upon the beach, forming distinct causeways in two places. The 

 columnar structure is everywhere very distinct, and the phenomena 

 similar to those met with on the Antrim coast, but on a less 

 gigantic scale. 



None of these islands are much more elevated than Table Island ; 

 and the soundings around them vary between 30 and 50 fathoms. 

 They are all more or less flat, and entirely devoid of trees or even 

 shrubs. 



Hai-tan Island, to the north-east of Formosa, is really a portion 

 of the coast of China. The seaward coast of Hai-tan Island consists 

 of perfectly bare rocks, which descend in smoothly rounded sur- 

 faces to the water's edge. The island appears to be a mass of 

 whinstone, with nothing better to relieve the eye than sandy 

 patches and one or two remarkably conspicuous hiUs of sand. 



Between Hai-tan Island and the mainland are numerous rocky 

 islands of a remarkably bold outline. On two of these I landed — 

 viz. on Middle Island, on the east side of the strait, and Black 

 Islet, on the west side. Middle Island is formed of blocks of trap- 

 pean rock piled up promiscuously and at various elevations to about 

 80 feet above the sea, the upper part being much disintegrated, 

 and forming a coarse barren soil, which supports a few flowering 

 plants and a scanty herbage. 



Black Islet, within sight of the last, is a mass of granite, 

 broken up and much disintegrated, all the upper surface being a 

 soil of coarse quartz sand. 



Immediately to the north of Formosa is a group of three islands, 

 called Pinnacle, Craig, and Agincourt Island respectively. The 



