392 /. Starkie Gardner — On Cretaceous Aporrha'idw. 



Of the masses here named there is some probability that the 

 gneissoid granite, with the connected masses of purer granite, is a 

 metamorphosed rock connected with the undoubtedly original sedi- 

 mentary gneiss of the coast-tract, and thus formed at the same time 

 as the stratified masses of the latter, and in the main under similar 

 circumstances. 



On the other hand, the inland granite is presumably of irruptive 

 origin. So considered, it is younger than the mica-slate group, the 

 stratified masses of which it has pierced, but older than the slate- 

 field of the Balsfjord, the stratified masses of which lie over the 

 granite, often with a slight angle of inclination, without any sub- 

 sequent intrusion being anywhere observable. 



The Gabbro and the hypersthenite break through the mica-slate 

 group, and partly also the Balsfjord slate group, and are therefore 

 younger than these, but older than the Baipas group. The green- 

 stone which traverses the Baipas group is younger than it, but 

 older than the Gaisa group. We have, therefore, here to distinguish 

 between the older Gabbro and the younger greenstone (younger 

 Gabbro). 



The age of the olivine rock cannot be accurately determined. It 

 is probably older than the Tromso mica-slate group. 



The following synoptical table will assist in elucidating this 

 subject : — ■ 



A. — Stratified Groups. 

 I. Primitive rock (probably Laurentian). 



II. Tromso mica-slate group (probably Huronian). 



III. Balsfjord slate-field (younger Cambrian, probably Taconian). 



IV. Tbe Alten and Kvcenangen group (Eaipas group), Silurian. 

 V. Golda group (Gaisa system), perhaps Devonian. 



VI. Jura formation, a quite locally-appearing section at Ando, with coal layers 

 (Ammonites, Belemnites, Pecten, etc.). 

 VII. Quaternary formation : — 



(a) Glacial period. 



(b) Post-glacial period. 



(1) Older section. 



(2) Younger section (the Gulf-stream period). 



B. — Unstratified. 

 I. Gneissoid granite (Laurentian). 

 II. Inland granite (post-Huronian). 



III. Gabbro, hypersthenite (post-Taconian) . 



IV. Greenstone (post- Silurian). 

 V. Serpentine. 



VI. Olivine stone. 



II. — On the Cretaceous Aporrha'i'd^:. 



By J. Starkie Gardner, F.G.S. 



(PLATE XII.) 



{Continued from page 298.) 



When I commenced these notes at the beginning of this year, I 



expressed a regret that " I cannot include the Aptien and Neocomian 



species, but the collections at present open to me are too meagre to 



give anything like a complete account of them. ... I have also 



reason to believe that many undescribed species exist from the Upper 



