Yes.
First, you should improve your ability of Reading and comprehension.
Second, you think it is a problem about the topic. However, judging from the question#,I think all these questions are among the hard group of the OG question. Questions in this group are more complex in logical structure, require better understanding of the meaning of the stimulus, and are very tricky in the arrangement of the answer choices.
Reading ability is a wide concept. As for CR, I think clearly seeing though the logical structure is the most important thing. You should know clearly what is the premise, what is the conclusion, and most important, what is the line of reasoning of the author--the approach taken by the author to support his conclusion with his premise.
As you said, all these staffs, such as fossil,pottery,and instruments , appear in the stimulus. Always another thing found later can build some relation with these staff and help the author get one conclusion. Nice job! You have already done it well. The next step is to find exactly how the author generate his conclusion by the appearance of this "another thing". Does he use correlation? Does he use conditional reasoning? What is the assumption in this conditional reasoning? Whether there is an causal-effect relationship in the stimulus? Take it easy and feel about your feeling.