152 Proceedings of the Royal Society of Victoria. 



Muddy Creek and in the (Spring Creek beds and found the result 

 to point in the same direction, namely, that the Spring Creek 

 beds are older than those of Muddy Creek. 



The force of some of the objections raised to our views by 

 Messrs. Tate and Dennant, especially as regards the value of the 

 polyzoal rock as a bench mark, cannot be gainsaid, but there are 

 others Avhich we are not at all prepared to allow. We are still 

 of opinion that the Spring Creek series is older than the Muddy 

 Creek one, and that the older volcanic rock is older than the 

 Muddy Creek beds and younger than part, at any I'ate, of the 

 Spring Creek series. 



As a matter of convenience we shall consider Messrs. Tate and 

 Dennant's objections in the order in which they appear in their 

 paper. 



In the first place (2, p. 116) the following sentence occurs in 

 their paper : — " At Maude, as is well known, tertiary deposits 

 occur both above and below a layer of basalt, which has been 

 described by the survey as a subsequent intercalation, but this 

 reading is disputed in the article referred to," that is, in our 

 papei'. From this passage it would, we think, naturally be 

 concluded that the volcanic rock of this section was regarded by 

 the officers of the survey as of more recent date than the marine 

 beds with which it is intercalated, and that it was in opposition 

 to their views that we regarded it as contemporaneous. In other 

 words, it was open to doubt if it really represented the older 

 volcanic, and that any conclusions we might draw from our view 

 of the case were to be received with caution. But the word 

 " subsequent " does not appear, as far as we can find, in any of 

 the references to the section. As a matter of fact our views on 

 this point are in complete accord with those of the survey, and 

 it was by means of this very section that the age of the older 

 volcanic rock was determioed by Selwyn for the colony generally. 

 What we did difier from the survey on was a very minor point. 

 The officers state in effect that after the main flow of basalt, of 

 about 100 feet in thickness, a period of quiescence followed, 

 during which a thin bed of limestone was deposited. Then a 

 thin sheet of basalt was poured out, covering tlie limestone and 

 metamorphosing it, and that then the deposition of limestone and 

 other marine beds was resumed. We hold that there is only one 



