The purpose of the author is to present a geological survey of the Backbone Ridge area in Burnet and Llano counties, Texas. During the summer of 1947 while enrolled in a geologic field course in McCullough County, it was noted that a new classification of the Cambrian and Ordovician formations In central Texas had been presented In the literature. It was noted at the same time that the Paleozoic rocks of the Llano uplift are more highly faulted than had been shown on previous geologic maps of the region. The writer concluded from field observations that the Backbone Ridge area was more complexly faulted then had been previously shown, and it was decided to test this conclusion by making a detailed geologic map of the area using the stratigraphic subdivisions recently established by Bridge, Barnes, and Cloud. A detailed study was made of these subdivisions and a large number of the type sections were visited. It was necessary to study the complete geologic history of the region in order that the events which involved the complex structural pattern and the present physiographic forms might be properly understood. The material contained in this report consists of data obtained from the literature and from field observations which were made in the area during the months of June and July of 1948. / text