Deep Boring in Chalk of Denmark. 175 



Fragments wliich appeared to be those of Sc. constridtis were found at 

 the depth of 1,580-1,590 feet. About this same depth, where it will 

 be remembered lar^e lumps of chalk were obtained, there occurred 

 Scalpellum cretcB, Memhranipora crassa, Marss., and a Terehratuliiia 

 of. ornata, Koem., all of which suggest a Skrivekridt fauna. The 

 marlstone (1,700-2,742 feet) yielded Metopaster tumidus, Spencer, 

 var. radiatiis, Spencer (1,920 feet), and Metopaster undulafus, Spencer 

 (2,015-2,070 feet). Both these Asteroids indicate a horizon not 

 lower than the 'middle mucronata'. PuUicipes fallax, Darw. 

 (2,070 feet), and Crania antiqua, Defr. (2,380 feet), suggest according 

 to the authors a ' mucronata ' or ' quadratus ' liorizon for the chalk 

 near the bottom of the boring. The occurrence of Belemnitella 

 lanceolata, v. Schloth., sp., at a depth of 2,648 feet seems to indicate, 

 together with the preceding evidence, that the boring had now 

 dehnitely entered 'quadratus' chalk. 



Besides this positive evidence it appears to the authors of these 

 notes that the fact that no plates of Marsupites and Uintacrinns were 

 found is good proof that these horizons were not reached. 



Ravn, in a general summary of the results obtained, states that 

 Moberg and Hennig in studying the Chalk of Scania find that the sea 

 broke over South Sweden in the Lower Senonian. The sea increased 

 in depth through the 'quadratus' and into the 'mucronata' period. 

 It then receded for a time (about the 'middle mucronata') and after- 

 wards increased in depth more quickly than before. 



These observations support the evidence from the boring in 

 Denmark. The analyses of the matei'ial from the boring (on samples 

 from each 50 feet) show that the marly chalk from the lowest point 

 is fairly rich in sandy particles, and that these particles, which imply 

 the proximity to the coast, decrease in quantity higher up. This is 

 followed by a definite increase in the proportion of sand at a depth 

 of about 2,250 feet, until at 2,100 feet there is a definite layer of 

 sand. The proportion of sand a second time decreases until we reach 

 a pure white chalk. This seems to prove that the lowest strata 

 reached by the boring were formed in a somewhat shallow sea, which 

 gradually increased in depth, again became more shallow, and finally 

 deepened rapidly. 



Ravn thinks that if the boring could be continued further the bore- 

 hole would soon find the shallow-water Lower Senonian deposits 

 which form the base of the Chalk in Denmark. 



Conclusions. 



The authors of the report are to be highly congratulated on the 

 careful manner in which they conducted their investigations, and on 

 the convincing detail w-hich they carefully set out. All the fossils 

 were submitted to paltEontologists familiar with the group which 

 they investigated. Elaborate chemical analyses were undertaken by 

 Professor Billmann, and these are of great help to the argument. 

 Records of the increase of temperature as the boring proceeded 

 downward were also made. 



The results obtained add interest to investigations upon the English 

 'mucronata', and especially the 'mucronata' of Norfolk. Although 



