import – Importing selected data from text files

I have a large number of text files in a folder with different names. These are the output data files from an experiment. Each text file has first 50 lines of text, followed by four columns of numerical data. For some analysis, I want to import the data in all these files to Mathematica in form of tables. However, there are two problems I am facing, will appreciate any help in this regard.

First, the names of these large number of text files are randomly chosen, and I don’t want to mention them manually. Is it possible to tell Mathematica to import all the text files in a folder irrespective of their names?

Second, while importing the data from each file, I want to crop first 50 rows and two columns (2 & 3). Basically I need numerical data in columns 1 and 4 only, from row 51 to end. How to do it? Each set of these two columns (2Xn table) can be named as the name of the text file from which they are taken.