1d convolution in a selected dimension

I would like to perform 1d convolution on the last dimension. I am putting two outputs from previous layers on top of each other to create additional dimension along which I would like to convolv, but I am Getting this error:
Expected 3-dimensional input for 3-dimensional weight [70, 1021, 2], but got 4-dimensional input of size [8, 1021, 70, 2] instead