APPENDIX 601 



The Mode of Observation. A thermometer made on the Sixe pattern 

 which I used several years ago for taking the bottom-temperatures of rivers, 

 was employed for the deeper temperatures, and at critical depths the 

 observations were always repeated. This instrument was compared after 

 each set of observations with an ordinary thermometer graduated on the 

 stem, which was compared with my standard thermometer provided with a 

 Kew certificate. . . . The observations in the Panama Roadstead have 

 been added for the sake of contrast. 



NOTE 75 (page 496) 



ON THE STRANDED MASSIVE CORALS APPARENTLY OF THE GENUS 

 PORITES FOUND ON THE COAST OF PERU AND NORTH CHILE, AT 

 ARICA (18 25' S.), CALLAO (12 3' S.), AND ANCON (n 45' S.) 



At Arica they occurred on the beach only. At Callao they also ex- 

 tended inland on the low spit at Punta for about 100 yards. At Ancon 

 they were found not only on the beach but also twenty or thirty paces 

 inland on the low adjoining plains. Their size varied from three inches to 

 three feet. They were all more or less rounded by wave action, and were 

 extensively burrowed by boring molluscs. Whilst some on the beach still 

 displayed the dried-up soft parts of the boring mollusc, others inland were 

 falling to pieces and undergoing chemical change. There was nothing to 

 indicate that the corals were recently alive ; and at Ancon they appeared 

 to have been torn off a rocky spit of andesite that had become exposed on 

 the beach during a recent movement of emergence, of which there is other 

 evidence on this coast. Further particulars are given on page 496. 



NOTE 76 (page 429) 

 STRANDED PUMICE ON ENGLISH AND SCANDINAVIAN BEACHES 



Sernander, in his description of the Atlantic drift of the Scandinavian 

 coast, refers to the occurrence of a small amount of true pumice. I have 

 found solitary fragments of acid pumice well rounded by wave-action at 

 Croyde Bay on the north coast of Devonshire, at the mouth of Salcombe 

 Harbour on the south coast of the same county, and at Maenporth, near 

 Falmouth, in Cornwall. Steamer slag, in some cases rudely simulating 

 pumice, is common on all the South of England beaches I have examined. 

 It is also common on the Scandinavian coasts, though seemingly regarded 

 by Helge Backstrom, who is quoted by Sernander, as derived from the 

 factories on the east coast of England. (See on these subjects a paper by 

 Helge Backstrom, " Uber angeschwemmte Bimsteine und Schlacken der 

 nordeuropaischen Kiisten " ; Bihang till K. Sv. V. A. Handl. Bd. 16. 

 Afd. 3, 1890 ; also a letter in Nature^ about 1886, by H. B. Guppy.) 



