Our principal purpose in writing this outline of the Geological History of Queensland was to provide a short text to meet the needs of the students of geology within the University of Queensland, but we have kept in mind also the teachers and students of geology in the secondary schools. It is hoped too that it may be of use to others interested in the geological history of the State who have not the time or the necessity to make a more complete study from the original sources.
The scope of the work is wide in space, embracing as it does, the whole area of the State of Queensland-some 670,000 square miles-and wider in time, ranging as it does over a thousand million years. To encompass these dimensions within a mere 100 pages has proved a difficult task. Geographical generalisations for such a large area inevitably tend to oversimplify what are in fact complex patterns of distribution. Further, as in any other short, simple outline of a long and complicated history, conciseness and simplicity could be achieved only at the expense of completeness and accuracy in detail.
The method adopted in these circumstances was to collect and examine all the available data and then present them in summarised form. This involved a certain amount of selection, but every effort was made to ensure that the facts as presented represent a well-balanced summary of the whole. It must be admitted however that the south-eastern part of the State, which is of particular interest to students at Brisbane, and about which more information is available, has received some added emphasis. With regard to the interpretation of the facts, the position was more difficult. Rival schemes of correlation are so numerous, and hypothetical restorations of gaps in the evidence so varied, that we felt compelled deliberately to select those explanations which in our judgment appeared most nearly adequate ; where other things were equal we selected the simplest. We have, too, used question marks rather · sparingly, in spite of the fact that the geological record of the State is crowded with unanswered queries. This arbitrary procedure was necessary if we were to avoid the welter of argument and controversy which characterises Queensland stratigraphical studies, and which we thought would be out of place in an outline such as this. Inevitably, as a result of the methods we were forced to adopt, the story as we have told it is incomplete and over simplified.
The material used in the preparation of this Outline has come from many and varied sources, and it is our wish that all these should be acknowledged in their proper places, However, the references would have been so numerous and the interruptions to the continuity of the text so frequent, that we decided to record our sources of information as bibliographic lists. Selected and incomplete as these are they may serve to indicate the degree of our indebtedness to other workers. It will be seen that they include many of the valuable publications of the Geological Survey of Queensland and other original papers from diverse sources. But the lists do not indicate the help we have received from discussions with the officers of the Geological Survey and our own colleagues for which we are most grateful. More particularly, and at the risk of appearing to make invidious distinctions, we wish especially to acknowledge the help we have received from one book, one map and one individual. The book is ''The Geology and Palaeontology of Queensland and New Guinea '' by Jack and Etheridge. Although published over fifty years ago this magnificent work remains a mine of information and a source of inspiration to those interested in the geology of the State. The map is the "New Geological Map of the Commonwealth of Australia” prepared by Sir T. W. Edgeworth David and published (together with a volume of "Explanatory Notes ") in 1932. That part of the map which includes this State is by far the best geological map of Queensland in existence and as such was of the greatest help. The individual is our colleague Dr. (Major) F. W. Whitehouse, who, when his duties as an officer in the Australian Army permitted, gave us freely of his extraordinarily wide an d intimate knowledge of the geology of Queensland.
In addition to the information derived directly from our numerous sources, and particularly from those just mentioned, we have introduced where we thought advisable or necessary certain new information and certain new interpretations hitherto unpublished, for which we personally must accept responsibility.
In addition to dealing with the more strictly stratigraphical aspects of the geological history of Queensland in some detail, an endeavour has also been made to outline briefly the more important earth movements and the igneous activity during each period and to give a synopsis of the deposits of economic importance.
Accompanying the text will be found a series of maps. A note of warning is necessary with regard to these, which have been prepared for two purposes. In the first place they show with some precision the localities from which fossils have been obtained and on which the ages and facies of the several series have been determined. Secondly, they give in broad outline a picture of the general distribution of the sediments of the different periods. They should not be regarded either as geological or palaeogeographical maps. They differ from the former in that they include more than the actual outcrops, · and from the latter in that they show less than the actual extent of the seas and lakes.
In addition to the purposes which moved us to write this work and which are set out at the beginning of the preface, is the hope that by bringing together the available information in this compact form we may encourage others to take part m unravelling the tangled skein of Queensland Stratigraphy.