Schematic notation for decoupling capacitor?
Omitting the supply rails and decoupling capacitors is a common shorthand in circuit diagrams.  It's admissible, when supply rails are not important for the discussion.

0.001 μF in the original post is not a decoupling capacitor.  It's a compensation capacitor between pins 1 and 8 of the CA3130 OpAmp.



fig.8 on p.9 in the datasheet.   Decoupling capacitors in this schematic are 0.01 μF, compensation capacitor in this schematic is 56 pF.