INTRODUCTION. 



Be it observed that this announcement is inserted in the 

 same number of the ( Annals ' which contains our memoir 

 above noticed. But more is to follow ! 



1876. New Laurentian Fossil. Nature,, May 4, 1876. 



Dr. W. B. Carpenter announces the discovery,, in " Harris, 

 of what is regarded by every palaeontologist who has seen 

 the specimen as an unquestionable organism." ..." The 

 fabric seems to have consisted of superposed layers of calcareous 

 shell- substance/' with spaces between them much thinner than 

 the layers, " filled up with calcite." ' ' Altogether I have no 

 hesitation in concurring with Prof. H. A. Nicholson, Prof. 

 Geikie, and Mr. Etheridge in affirming it to be so unmis- 

 takably organic, that, if it be claimed by mineralogists as a 

 ' rock-structure/ a large number of universally accepted fossils 

 will have to go along with it." 



Our reference (preceding page) to what proves to be the same 

 " unquestionable organism " brought out, as was to be expected, 

 the following letters, which, though commendable in one respect, 

 ignore altogether the brief remarks made by us respecting its 

 being granite, consisting of layers of quartz and feldspar ! 



1876, Supposed New Laurentian Fossil. Nature, May 25, 1876. 



Dr. W. B. Carpenter. 



" I lose no time in making known to the readers of ' Nature ' 

 that the notice of a New Laurentian Fossil which I published in 

 its columns three weeks since, was written under a complete 

 misapprehension of the real nature of the body. So far from 

 being calcareous, as I had been led to believe by the information 

 I had received from the geologist who found the specimen, 

 it proves to consist of alternating layers of felspar and quartz 

 the former simulating an organic structure like that of Stroma- 

 topora, and the latter occupying what had been supposed to be 

 cavities of that structure together constituting what is known 

 to petrologists as ' graphic granite ;' " " and what had seemed to 

 be a vertical tubular structure, proving to be mere striation " (see 

 p. xxxiii) . " The examination of numerous sections of this body, 



