334 Mr. W. King on some Shells and other Invertebrate Forms 



ridges of that vast country ; for great would be my pleasure to 

 learn, that through the application of Cornish skill, such regions 

 should be converted into a British " El Dorado/^ 



Requesting you to pardon this little digression, which after 

 all may be turned to profit, and hoping that you will be as proud 

 as I am of the connexion which is now established between Corn- 

 wall and Siluria, 



Believe me to be, my dear Sir Charles, 

 Yours most faithfully, 



U. I. MURCHISON. 



XXXVII. — First series of Supplementary Notes to a former Paper j 

 entitled " An Account of some Shells and other Invertebrate 

 Forms found on the coast of Northumberland and of Durham^, '^ 

 By William King, Curator of the Newcastle Museum. 



Having lately read with some attention Professor Edward 

 Forbes's highly philosophical paper on ^' The Geological relations 

 of the existing Fauna and Flora of the British Isles,'' published 

 in the first volume of the ^ Memoirs of the Geological Survey of 

 Great Britain,' &c., I have been induced to make a few remarks 

 on the depth of habitat of certain species and varieties living on 

 the coasts of Durham and Northumberland. 



Professor Forbes divides the bottom of the British seas into 

 four regions or zones according to depth of water and biological 

 peculiarities. " The first or Littoral zone is that tract which lies 

 between the high and low water marks," and inhabited by some 

 common species of Fucus, Littorinas, Purpura lapillus, &c. " The 

 second or Laminarian zone is that land-encircling belt which com- 

 mences at low water mark and extends to a depth of from seven 

 to fifteen fathoms. The great tangle sea-weeds form miniature 

 forests in this region," which is also tenanted by Rissoas, Lacu- 

 nas, Patella pellucida, Pullastras, &c. The third is the Coralline 

 zone, the vertical range of which is from " fifteen to about fifty 

 fathoms ; its chief development between twenty-five and thirty-five 



I would specially direct attention, now that its true characters have been 

 opened out to geographers and naturalists by the undaunted and able 

 explorations of Dr. Leichhardt. Some of the tracts recently' passed through 

 with so much zeal, by the Surveyor-General of the colony, Sir Thomas 

 Mitchell, may also prove valuable in gold, though they lie further from the 

 axis of elevation. In the mean time, gold ore has been found on the other 

 side of the Australian continent, in the ridges which extend northwards 

 from Adelaide towards the scene of the adventurous and toilsome journey of 

 Major Sturt. These gallant geographers, the pioneers of civilization, are 

 explaining to us the condition of tracts which thousands of our countrymen 

 may soon colonize with the best effects. — London, April 12, 1847. — R. I. M. 

 * Annals and Magazine of Natural History, vol. xviii. pp. 233 — 251. 



